In the Spring 2010 issue of the EMC Society Newsletter (Issue No. 225), we published an article on my visit (Associate Editor Hoolihan) to the UEC Museum of Communications in Tokyo, Japan on March 27, 2010. This article is an update on the Museum including a post-earthquake report.
When I visited the Museum in March of 2010, the Museum was waiting for the delivery of a special tube from Sweden. The tube was delivered from Sweden in early 2011; it is on loan from the Teknisa Museet Sweden (Technical Museum of Sweden) in Stockholm, Sweden. The tube is called the Lieben Tube. The tube is now on display in a special, very-strong and anti-earthquake display case in Room 7 of the Museum.
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| The Lieben Tube on display at the Museum of Communications in Tokyo, Japan. |
The Lieben Tube is a mercury-vapor filled triode. The tube was invented by Austria in 1906 and, during World War I, the tube was used in the battlefield as a repeater amplifier for the wired telephone system of the German Army. There are only two of the Lieben Tubes in existence today.
In 1906, three Austrians – Robert von Lieben, Eugene Reisz, and Sigmund Strauss – developed the mercury-vapor filled triode. In 1912, a German company began to produce the Lieben Tube; the company was AEG-Telefunken. But, the Lieben Tube was very unstable and its critical characteristics were variable due to the anomaly of the mercury-vapor. Also, the Lieben Tube had a short life which made it impractical to use in real work. So, it was replaced by tubes that were of a high-vacuum design.
The structure of the Lieben Tube was unique; its two large glass tubes are connected at the center as shown in the accompanying photos. An aluminum grid plate with holes “like a lotus flower” joins the two glass tubes to each other.
An anode is located in the upper tube and it is structured as a narrow spiral coil with 2 mm diameter aluminum wire. The cathode is located in the lower tube and it consists of a platinum ribbon coated with an oxide material. The cathode is structured like a cage with folded ribbons with an oxide coating (BaO and CaO) on the ribbon facing outwards.
A small glass vessel is fitted at the bottom of the lower tube; it has an amalgam that releases the mercury vapor.
The tube is approximately 30 cm long with a 10 cm diameter. The cathode (filament) is operated at 30 volts at about 2 amps. The anode voltage is 200 volts DC with a current of 10–11 milliamps DC. The mercury vapor pressure is 0.01 mm Hg. The amplitude factor is mu = 33, the operating temperature is 15–30 degrees Centigrade, and the useful lifetime was between 1000 and 3000 hours.
The Good News is that the Earthquake-Resistant Case for the Lieben Tube Worked Exactly as Designed and the March Earthquake (magnitude 9) in Japan did not do Any Damage to the Lieben Tube!
The Museum in Tokyo has also added a Photomultiplier tube for Neutrino Detection. This tube was used at the world famous Kamiokande Observatory in Nagano, Japan. The tube is classified as an extremely low-noise super-high sensitivity photoelectric cell with extreme high-gain photomultiplier.
Kamiokande Observatory of ICPR of the University of Tokyo was built for the research and verification of nucleon decay phenomena. The observatory is located at Kamioka City in the Nagano prefecture of Japan.
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The display of the photomultiplier tube for nuetrino detection
at the Museum of Communications in Japan is signed by its inventor, Professor Masatoshi Koshiba of the University of
Tokyo. Professor Koshiba was awarded the Nobel Prize for
Physics in 2002 for research accomplished using this tube. |
A photomultiplier tube for nuetrino detection used at the world famous Kamiokande Observatory in Nagaon, Japan. |
The observatory was built with a huge cylindrical tank filled with 3000 tons of super-pure water; the tank was built 1000 meters below ground level. The inside surface of the tank is covered with 11,000 of the extremely sensitive photomultiplier tubes for detection of very weak fluorescent light emitted by the nucleon decay after a collision with a high-speed neutrino. The photomultiplier tube is designed to be similar in style to a 20 inch
CRT which was developed and made by Hamamatsu Photonics Co. in Hamamatsu, Japan.
The entire project was developed and directed by Emeritus Professor Masatoshi Koshiba of the University of Tokyo; it was initiated in 1983. On the 23rd of February in 1987, the project detected the world’s first detection of light due to a collision of a neutrino with the water. It is believed the neutrino came from the Super Nova of the Great Magellan Nebula (SN1987A).
Professor Koshiba was awarded the Nobel Prize for physics in 2002 for this detection result. The tube in the museum is autographed by Professor Koshiba. EMC
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