A Crookes tube: light and dark. Electrons (cathode rays) travel in straight lines from the cathode (left), as shown by the shadow cast by the metal Maltese cross on the fluorescence of the righthand glass wall of the tube. The anode is the electrode at the bottom.
A Crookes tube (also Crookes–Hittorf tube)[1] is an early experimental electrical discharge tube, with partial vacuum, invented by English physicist William Crookes[2] and others around 1869-1875,[3] in which cathode rays, streams of electrons, were discovered.[4]
Developed from the earlier Geissler tube, the Crookes tube consists of a partially evacuated glass bulb of various shapes, with two metal electrodes, the cathode and the anode, one at either end. When a high voltage is applied between the electrodes, cathode rays (electrons) are projected in straight lines from the cathode. It was used by Crookes, Johann Hittorf, Julius Plücker, Eugen Goldstein, Heinrich Hertz, Philipp Lenard, Kristian Birkeland and others to discover the properties of cathode rays, culminating in J.J. Thomson's 1897 identification of cathode rays as negatively charged particles, which were later named electrons. Crookes tubes are now used only for demonstrating cathode rays.
Wilhelm Röntgen discovered X-rays using the Crookes tube in 1895. The term Crookes tube is also used for the first generation, cold cathode X-ray tubes,[5] which evolved from the experimental Crookes tubes and were used until about 1920.
Power off.
Without magnet, rays travel straight.
With magnet, rays are bent up.
With magnet reversed, rays are bent down.
A Crookes tube demonstrating magnetic deflection. With a magnet held at the neck of the tube (right) the rays are bent upward or downward, perpendicular to the horizontal magnetic field, so the green fluorescent patch appears higher or lower. Residual air in the tube glows pink when it is struck by electrons.
^T. A. Delchar, Physics in Medical Diagnosis, Springer, 1997, p. 135.
^Crookes, William (December 1878). "On the illumination of lines of molecular pressure, and the trajectory of molecules". Phil. Trans. 170: 135–164. doi:10.1098/rstl.1879.0065. S2CID 122178245.
^"Crookes Tube". The New International Encyclopedia. Vol. 5. Dodd, Mead & Co. 1902. p. 470. Retrieved 2008-11-11.
^"Crookes tube". The Columbia Electronic Encyclopedia, 6th Ed. Columbia Univ. Press. 2007. Retrieved 2008-11-11.
^Mosby's Dental Dictionary, 2nd ed., 2008, Elsevier, Inc. cited in "X-ray tube". The Free Dictionary. Farlex, Inc. 2008. Retrieved 2008-11-11.
A Crookestube (also Crookes–Hittorf tube) is an early experimental electrical discharge tube, with partial vacuum, invented by English physicist William...
named the mineral crookesite in honor of Sir William Crookes. Crookes developed the Crookestube, investigating cathode rays. He published numerous papers...
dark space" or "Crookes dark space". Crookes found that as he pumped more air out of the tubes, the Faraday dark space spread down the tube from the cathode...
The Crookes radiometer (also known as a light mill) consists of an airtight glass bulb containing a partial vacuum, with a set of vanes which are mounted...
state primary school. Crookes attended the fee-paying Portland Place School in central London for secondary education. Crookes gained interest in singing...
discharge tube (or Crookestube), and so described by Sir William Crookes in 1879 (he called it "radiant matter"). The nature of the Crookestube "cathode...
research with evacuated tubes, such as the Geissler and Crookestubes. The many scientists and inventors who experimented with such tubes include Thomas Edison...
that is created by certain types of gas-discharge tubes. They were first observed in Crookestubes during experiments by the German scientist Eugen Goldstein...
using a fluorescent screen painted with barium platinocyanide and a Crookestube which he had wrapped in black cardboard to shield its fluorescent glow...
Taking an X-ray image with early Crookestube apparatus in 1896. The Crookestube is visible in the centre. The standing man is viewing his hand with a...
also reported burns. Thomson deliberately exposed a finger to an X-ray tube over a period of time and suffered pain, swelling, and blistering. Other...
cellar, arm themselves with military flamethrowers, and outfit a modified Crookestube in the hopes of destroying any supernatural presence they might find...
modification of the Crookestube, with a phosphor-coated screen. Braun was the first to conceive the use of a CRT as a display device. The Braun tube became the...
when they hit a tube's glass walls and, when interrupted by a solid object, cast a shadow. 1869 William Crookes Invented the Crookestube. 1873 Willoughby...
modification of the Crookestube with a phosphor-coated screen. The Braun tube became the foundation of 20th century television. A cathode ray tube was successfully...
Thomson discovered the electron through his work on cathode rays. A Crookestube is a sealed glass container in which two electrodes are separated by...
discharge tubes (Crookestubes) and the influence of magnetic fields on the glow. Later, in 1869, Johann Wilhelm Hittorf studied discharge tubes with energy...
100 mm, which is on the order of everyday objects such as vacuum tubes. The Crookes radiometer turns when the MFP is larger than the size of the vanes...
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