Grace's Guide

British Industrial History

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20th Century Electronics

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20th Century Electronics - manufactures of cathode ray and Geiger-Müller tubes; specialists in radiation detection and optical sensing. Now trading as Centronic

Gilbert Tomes had worked in the research laboratory of Baird Television before working with Alec Tidmarsh at Cinema-Television Ltd where they manufactured and developed photocells. His innovations combined with his hobby of beekeeping led to the invention of a Queen Bee Detector, which made use of counter technology adapted from the work of the German scientists Geiger and Müller, to monitor movement within a hive by detecting the radioactivity from a spot of luminous paint applied to the body of the queen.

1945 Company founded by Gilbert Tomes and Alec Tidmarsh in a bedroom of Tomes' house in Kent.

1949 Became a limited company, 20th Century Electronics Limited; Tomes became sole owner.

1951 increase in demand for Geiger-Müller tubes; many new types introduced.

1953 moved to new, purpose-built, premises near Croydon to accommodate an increase in the workforce; development of devices for detection of neutrons. In conjunction with UKAEA, produced Europe's first Boron Fluoride neutron detectors. A 50 foot tower was built for a distillation column to separate boron isotopes, the world's first commercial source of boron-10.

1957 Development of photoelectric devices and glass photomultiplier tubes, where were used in the first UK satellite. Manufacture of metal ionisation chambers for the measurement of radiation in nuclear reactors, supplied to nuclear reactors worldwide.

1960 Further extensions to accommodate extra 100 staff.

Early 1960's: Developed solid state silicon detectors for nuclear applications, and later semiconductor devices for optical sensing for various applications.

1968 Development of quadrupole mass spectrometers for gas analysis, based on development of its own such instrument for the boron-10 distillation process. Also further factory extension to accommodate 350. employees

1970s Suppliers to nuclear power industry included the supply of reactor control detectors for Advanced Gas-cooled Reactors (AGRs). Also manufactured neutron detectors for nuclear power stations worldwide (notably the Canadian CANDU reactors) and for defence applications. Later this also provided a significant spares business.

1978 Trading name of company changed to Centronic Ltd. Formation of Centronic Optical Systems to meet demand for light-measurement.

1980 Production of silicon photodiodes for laser detection which were applied in military training for various weapons.

1982 First Castle Electronics purchased Centronic Ltd.

1986 Morgan Crucible Co plc took over the First Castle Group.

Early 1990s: ceased manufacturing photomultipliers, cathode ray tubes and mass spectrometers. Weapons simulation business sold. Acquisition of the R. A. Stephens dosimetry business. New product line in neutron detection equipment for use in nuclear steam-raising plant for marine propulsion.

1992 Acquired ZP range of Geiger-Müller tubes from Philips.

1999 Isotope manufacturing capability sold to Eagle-Picher Technologies, the world's leading supplier of boron products.

2000 Management buyout.

2003 Acquisition of Solatell and Raditec.

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