Editing Metal detector (section)

===Security screening===
[[File:Flughafenkontrolle.jpg|thumb|Metal detectors at [[Berlin Schönefeld Airport]]]]

In 1926, two Leipzig, Germany scientists installed a walk-though enclosure at a factory, to ensure that employees were not exiting with prohibited metallic items.<ref>[https://books.google.com/books?id=L5c1AQAAIAAJ&pg=1408 "The Radio Watchman at the Gate"], April 1926, Dr. K. Schuett, ''Radio News'', April 1926, pp. 1408, 1493.</ref>

A series of [[aircraft hijacking]]s led the United States in 1972 to adopt metal detector technology to screen airline passengers, initially using [[magnetometers]] that were originally designed for logging operations to detect [[Tree spiking|spikes in trees]].<ref>{{Cite web|url=https://savvytraveler.publicradio.org/show/features/2000/20000915/security.shtml|title=The History of Airport Security|website=savvytraveler.publicradio.org}}</ref> The Finnish company [[Outokumpu]] adapted mining metal detectors in the 1970s, still housed in a large cylindrical pipe, to make a commercial walk-through security detector.<ref>Jarvi, A, Leinonen, E, Thompson, M, and Valkonen K, ''Designing Modern Walk-through Metal Detectors, Access Security Screening: Challenges and Solutions'', ASTM STP 1127 TP Tsacoumis Ed, American Society for Testing of Materials, Philadelphia 1992, pp. 21–25
</ref> The development of these systems continued in a spin-off company and systems branded as [[Rapiscan Systems|Metor Metal Detectors]] evolved in the form of the rectangular gantry now standard in airports. In common with the developments in other uses of metal detectors both alternating current and pulse systems are used, and the design of the coils and the electronics has moved forward to improve the discrimination of these systems. In 1995 systems such as the Metor 200 appeared with the ability to indicate the approximate height of the metal object above the ground, enabling security personnel to more rapidly locate the source of the signal. Smaller hand held metal detectors are also used to locate a metal object on a person more precisely.