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Cathode ray tube - Wikipedia, the free encyclopedia Cathode rays exist in the form of streams of high speed electrons emitted from the heating of cathode inside a vacuum tube. The tube for this kind of use is longer and narrower, and deflection is done by applying an electrical field via deflection plates built into the tube's neck. The earliest version of the CRT was a cold-cathode diode, a modification of the Crookes tube with a phosphor-coated screen, sometimes called a Braun tube. en.wikipedia.org /wiki/Cathode_ray_tube   (2244 words)

Cathode ray - Wikipedia, the free encyclopedia Cathode rays propagate in a straight line in the absence of external influences, but are deflected by electric or magnetic fields (which can be produced by placing high-voltage electrodes or magnets outside the vacuum tube - this explains the effect of magnets on a TV screen). Cathode rays were first produced by Geissler tubes. Cathode rays are streams of electrons observed in vacuum tubes, i.e. en.wikipedia.org /wiki/Cathode_ray   (384 words)

cathode-ray_tube [n] a vacuum tube in which a hot cathode emits a beam of electrons that pass through a high voltage anode and are focused or deflected before hitting a phosphorescent screen. lookwayup.com /lwu.exe/lwu/d?s=f&w=cathode-ray_tube   (31 words)

X-ray - Wikipedia, the free encyclopedia When placing an X-ray tube on the opposite side of a wooden door Röntgen saw the same blue glow seeming to emanate from the eye itself, but thought his observations were spurious due to the fact that he only saw the effect when he used one type of tube. Later he realized that the tube which created the effect was the only one which produced X-rays powerful enough to make the glow plainly visible and the experiment was thereafter repeated readily. Hard X-rays overlap the range of "long"-wavelength (lower energy) gamma rays, however the distinction between the two terms depends on the source of the radiation, not its wavelength: X-ray photons are generated by energetic electron processes, gamma rays by transitions within atomic nuclei. en.wikipedia.org /wiki/X-ray   (2573 words)

X-ray tube - Wikipedia, the free encyclopedia The development of X-Ray tubes was an important historical event which enabled the field of radiology, for both imaging and treatment applications. As with any vacuum tube, there is a cathode to emit electrons into the vacuum and an anode to collect the electrons, thus establishing a flow of electrical current through the tube. In the Coolidge tube, the electrons are produced by a tungsten filament heated by an electric current (thermionic effect, also used for the television devices). en.wikipedia.org /wiki/X-ray_tube   (1075 words)

X-ray tube comprising an exit window - US Patent 5367553 An x-ray tube as claimed in claim 1 wherein in the cathode a filament is provided with supports which are constructed, dimensioned, and located so that the portion of the filament between the supports is at a uniform temperature in the vicinity of an emission temperature of the cathode. An X-ray tube as claimed in claim 8 wherein the cathode comprises a filament provided with supports which are constructed, dimensioned and located so that a comparatively large part of the filament is at a uniform temperature in the vicinity of an emission temperature of the cathode. An X-ray tube as claimed in claim 2 wherein the anode target face is situated at a minimum distance from the exit window, which distance is determined by an electrostatic potential difference between the anode and the radiation exit window. www.patentstorm.us /patents/5367553.html   (2576 words)

MSN Encarta - X Ray X rays were discovered accidentally in 1895 by the German physicist Wilhelm Conrad Roentgen while he was studying cathode rays in a high-voltage, gaseous-discharge tube. Both light and X rays are produced by transitions of electrons that orbit atoms, light by the transitions of outer electrons and X rays by the transitions of inner electrons. Much of the energy of the electrons is lost in heat; the remainder produces X rays by causing changes in the target's atoms as a result of the impact. encarta.msn.com /encnet/refpages/RefArticle.aspx?refid=761579196   (1070 words)

Mysterious Rays But when the German physicist Heinrich Hertz passed the rays through an electric field created by metal plates inside a cathode ray tube, the rays were not deflected in the way that would be expected of electrically charged particles. Cathode rays are not only material particles, he suggested, but in fact the building blocks of the atom: they are the long-sought basic unit of all matter in the universe. When Lenard passed cathode rays through a metal foil and measured how far they traveled through various gases, he concluded that if these were particles, they had to be very small. www.aip.org /history/electron/jjrays.htm   (451 words)

cathode-ray tube The tube itself is glass and coated inside with a black graphite conducting paint, which is connected to one of three anodes. A heated filament heats a metal-oxide coated cathode that emits electrons which pass through a positively charged anode that is held at several thousand volts and accelerates the electrons to a high speed beam. Vacuum tube in which a beam of electrons is produced and focused onto a fluorescent screen. www.tiscali.co.uk /reference/encyclopaedia/hutchinson/m0015949.html   (196 words)

Cathode-ray tube The cathode-ray tube (CRT) is one of the main elements of an oscilloscope. The tubes are produced with electrostatic and electromagnetic control, where electrostatic or magnetic fields deviate the electron beam respectively. CRT consists of the glass bulb evacuated to a high vacuum, the cathode (a source of electrons), cathode heater, electrodes for brightness and focus control, several accelerating anodes, the pairs of horizontal and vertical capacitor plates deviating the electron beam, and fluorescing screen. physics.nad.ru /Physics/English/osc_txt.htm   (304 words)

MONTEST-LCD monitor tester, Video Primer, Cathode Ray Tube CRT Located closest to the heated cathode is a round disc, approximately the size and the shape of a dime with a small hole in the center. It is ironic that although the vacuum tube industry has been reduced to a mere shadow of what it was in the early days of electronics, the CRT, the sole volume survivor of the vacuum tube days, appears as though it will be with us for many years to come. The CRT was designed in the 1920's and although several changes have been made to the original design, the changes to the basic structure have been relatively minor. www.montest.com /mon-apps.html   (1626 words)

X-ray tube --  Encyclopædia Britannica The German physicist Wilhelm Conrad Röntgen discovered X rays in 1895 by accident while studying cathode rays in a low-pressure gas discharge tube. X rays were discovered during the course of research into the effects of high-voltage electricity on gases. Cathode rays focused on a hard target (anticathode) produce X rays or focused on a small object in a vacuum generate very high temperatures (cathode-ray furnace). www.britannica.com /eb/article-9077661   (916 words)

84585.011108&ELEMENT_SET=DECL Tube collimators 272 are a stack of tubes; X rays pass through the centers of the tubes and in the open spaces between tubes. X rays 214 emitted by the sample 206 are transmitted through the sample 206 holding volume, through the anode-window 198, through the transmission cathode 208, and detected by a first detector 216. X rays 156 emitted by the electron-irradiated sample 152 are detected by an external, non-imaging, spectral detector 158 viewing the sample through the transmission cathode 162. www.wipo.int /cgi-pct/guest/getbykey5?KEY=01/84585.011108&ELEMENT_SET=DECL   (10490 words)

X-ray tube anode cooling device and systems incorporating same - US Patent 6430260 The x-ray tube 12 is disposed within the center section 18 of the assembly unit 10 in a fluid-filled chamber 20 formed by a casing 22. However, the high temperatures caused by this energy subject the x-ray tube 12 and its components to high thermal stresses that are problematic in the operation and reliability of the x-ray tube 12 and that reduce its throughput. The high temperatures encountered within an x-ray tube also reduce the scanning performance or throughput of the tube, which is a function of the maximum operating temperature, and specifically the anode target and bearing temperatures, of the tube. www.patentstorm.us /patents/6430260.html   (5487 words)

"Universal" Coolidge X-ray Tube If the alternating current causes the potential across the tube to change so that the "cathode" is positive and the "anode" negative, there is the possibility that the electron stream in the tube could reverse so that x-rays were being produced by electrons striking the cathode. Valve tubes are essentially self-rectifying x-ray tubes that are designed to produce as low an intensity of x-rays as possible. Electrons are supposed to go from the heated filament of the cathode to the anode (target) where the x-rays are produced. www.orau.org /ptp/collection/xraytubescoolidge/valvetubeinfo.htm   (702 words)

Collecting and Recollecting: Medical Museum: University of Iowa Health Care: Gifts from the Recent Past X ray tubes used in radiology today are based on the design of this tube by William Coolidge, a physicist at the General Electric Research Laboratory in the early 1900's. Coolidge's tube was a vacuum that used an electric filament to generate the electrons which would produce the X rays. The earliest X ray sources were partially evacuated glass tubes which would not work unless a residue of gas remained inside. www.uihealthcare.com /depts/medmuseum/galleryexhibits/collectingfrompast/xray/xray.html   (1356 words)

ChemTeam: Cathode Ray Tube History As concerning the nature of the cathode ray, the Germans tended to the explanation that cathode rays were a wave (like light), whereas the British tended to believe that the cathode ray was a particle. Philipp von Lenard develops a cathode-ray tube with a thin aluminum window that permits the rays to escape, allowing the rays to be studied in the open air. 1855 German inventor Heinrich Geissler develops mercury pump - produces first good vacuum tubes, these tubes, as modified by Sir William Crookes, become the first to produce cathode rays, leading eventually to the discovery of the electron (and a bit farther down the road to television). dbhs.wvusd.k12.ca.us /webdocs/AtomicStructure/Disc-of-Electron-History.html   (799 words)

Cathode Ray Tube Tube The cathode ray tube is a sealed glass tube from which most of the air has been removed. Glass tube A piece of glass that connects the cathode ray tube to the stand. Click on part of the cathode ray tube to see a description of that part. dwb.unl.edu /Teacher/NSF/C03/C03Links/www.chem.uiuc.edu/demos/cathode.html   (178 words)

Electronics 29 The cathode-ray tube oscilloscope is an experiment that I had thought was beyond the scope of these pages, mainly because of the cost and difficulty of obtaining the components. The portion of the tube from the deflecting plates to the screen is accessible, so that a solenoid can be slipped over the end of the tube for possible experiments, such as the determination of e/m. The common picture tube is a CRT with magnetic focussing and deflection, often containing three electron beams that are directed to separate phosphor spots to display different colors, and which are modulated to display different intensities. www.du.edu /~etuttle/electron/elect29.htm   (2546 words)

cathode-ray tube on Encyclopedia.com CATHODE-RAY TUBE [cathode-ray tube] special-purpose electron tube in which electrons are accelerated by high-voltage anodes, formed into a beam by focusing electrodes, and projected toward a phosphorescent screen that forms one face of the tube. Cathode-ray tubes are used in television sets, computer monitors, automated teller machines, oscilloscopes, and radar displays. Some cathode-ray tubes can produce multiple beams of electrons and have phosphor screens that are capable of displaying more than one color. www.encyclopedia.com /html/c1/cathoder.asp   (286 words)

CATHODE RAY TUBE MANUFACTURING AND RECYCLING: Under the Glass-to-Glass Rule, after CRT glass is separated from the housing of CRT-containing devices, the glass is exempted from the requirements of the UWR. The CRT glass industry’s ability to limit the use of lead in the manufacturer of new CRTs is a significant contribution to the electronic industry’s overall effort to reduce the use of substances of concern, and therefore the environmental impact of electronics manufacturing and the end-of-life electronics recycling and disposal. CRT glass manufacturers have a high degree of confidence as to the composition of this recycled cullet since they know the glass was produced by their facility. www.nsc.org /ehc/epr2/nardone/nardone.htm   (4809 words)

Toshiba America Medical Systems: Radiology: Vascular X-Ray: Infinix VC: X-Ray Tube To increase your clinical capabilities, you need an X-ray tube that allows you to perform a wide range of interventional and diagnostic exams. And, its cooling capacity is two times greater than air-cooled tubes so that there are fewer cooling delays between exams for higher throughput. Tube voltage, tube current and pulse width can be set to vary automatically according to the changes in object thickness, thereby ensuring uniform image density. www.medical.toshiba.com /clinical/radiology/infinixvc-212-219-416.htm   (254 words)

NMAH: Roentgen X-Ray Tube This tube was purchased from a private owner in Germany and presented to the Smithsonian Institution in 1956 by the General Electric Company's X-ray Department of Milwaukee, Wisc. It is part of a very large and rich radiology collection at NMAH. This is one of the first x-ray tubes used by physicist Wilhelm Conrad Roentgen (1845�), who discovered this new form of radiation at the University of Wurzburg in Germany, on November 8, 1895. While experimenting with cathode rays by passing an electric current through a glass vacuum tube covered with black paper, he noticed an unexpected green glow on a little screen covered with phosphorescent paint lying on his bench. americanhistory.si.edu /collections/object.cfm?key=35&objkey=112   (196 words)

General Electric "Universal" X-ray Tube (ca. 1920s) This tube is not licensed to be re-exhausted or repaired, nor is the metal therein contained licensed to be used except in this particular tube. The filaments for the fine focus tubes were flat spirals like this one while those for the medium and coarse focus tubes took the form of a slightly conical spiral. The shape of the cathode filament (photo to left) indicates that this is a fine focus tube. www.orau.org /ptp/collection/xraytubescoolidge/coolidge.htm   (194 words)

X-ray tube having multiple cathode filaments - Patent 4799248 A common failure mode for X-ray tubes, particularly grid controlled tubes, is a short circuit between the cathode filament and the cathode cup to which the filament is mounted. The X-ray tube is housed within an enclosure which in addition to positioning the X-ray tube for radiating a region of interest, provides high voltage connectors for coupling high voltage energization signals to the X-ray tube cathode and anode. In this way, in the event of a tube failure due to filament shorting, an immediate recovery mode is possible wherein the switch actuator is toggled and a functioning X-ray tube is immediately for use. www.freepatentsonline.com /4799248.html   (2833 words)

X-Ray Generators The positive terminal of an x-ray tube is called the anode, it serves three important functions, (1) it provides a complete circuit for purposes of accelerating the electrons, (2) it houses the target material, and (3) it helps to cool the tube. The voltage being supplied to the anode is referred to as the tube voltage, and is primarily measured in kilovolts. If the heat in a tube was ignored, the target material that is embedded in the anode would be destroyed in a short period of time. www.ndt-ed.org /EducationResources/HighSchool/Radiography/xraygenerators.htm   (1917 words)

Radiation Control Measures for Analytical X-Ray Equipment Each x-ray tube housing must be so constructed that with all shutters closed the leakage radiation measured at a distance of 5 cm from its surface is not capable of producing a dose in excess of 2.5 mrem in one hour at any specified tube rating. The primary on-off switch for each tube must include a visual indication of the tube status, in the form of a warning light on the control console and a warning light on the tube housing, wired so that the x-ray tube cannot be energized if the warning light fails. Only properly trained maintenance personnel may install, repair, or make other than routine modifications to the x-ray generating apparatus and the tube housing apparatus complex. www.asu.edu /radiationsafety/x-ray/chap_5.html   (930 words)

USATODAY.com - Koreans try to save cathode-ray tube The South Korean manufacturer is referring to cathode-ray tube, or CRT, televisions &; the heavy boxes that have dominated the business since television was introduced at the New York World's Fair in 1939. CRTs — which some videophiles insist produce the best pictures — use a gun that fires electrons in a heavy, glass tube to light phosphors, far different from flat-panel TVs. Yet Samsung and a South Korean rival, LG Electronics Co., are refusing to abandon the old-style tube TVs entirely. www.usatoday.com /tech/products/gear/2005-08-14-koreans-cathode_x.htm   (953 words)

Science Projects - Tesla Coil, Laser, Cathode Ray Tube The cathode ray tube is a vacuum tube, produced without a vacuum pump, and it's made from only a 1/2" dia. Flying home, I put the tube together in less than 10 minutes, hooked it up to the Tesla Coil and a strangely blue eerie glow was dancing through the tube and I could plainly see the Faraday dark space at the cathode. Laser radiation is produced when a gas discharge tube is highly evacuated and then filled with gas, placed between two mirrors forming a resonant optical cavity. www.primeline-america.com /bckps/pages/science   (802 words)

ChemTeam: Cathode Ray Tube Results There were a number of results gathered over the years by cathode ray tube researchers. 4) Although there was some speculation that the cathode rays were negatively charged, it is not shown to be true by experiment until 1895, just two years before Thomson announces the electron. The cathode rays bend toward the positive pole, confirming that cathode rays is negatively charged. dbhs.wvusd.k12.ca.us /webdocs/AtomicStructure/Disc-of-Electron-Results.html   (589 words)

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