page_title: Fixed Survey Meter
section_title: Overview
hierarchical_section_title: Fixed Survey Meter / Overview
caption_attribution_description: Photo showing the early Royal Observer Corps Fixed asurvey Meter in its wooden case.
context_page_description: The Fixed Survey Meter was a specialist detection instrument used by the Royal Observer Corps during the Cold War between 1958 and 1982 to detect ionising radiation from nuclear fallout generated by a ground burst.
context_section_description: The instrument was designed and built by the Atomic Weapons Establishment at Aldermaston as a replacement for the Radiac Survey Meter No 2 which could only be used above ground. The Royal Observer Corps’ need was for an instrument that could be read from inside the protected environment on the underground post.
  The instrument had an analogue mechanical dial with a pivoted needle indicator on a scale that covered 0.1 roentgens to 500 roentgens. Powered by three obsolete high voltage batteries (15 volt and 30 volt), that had to be specially manufactured, the meter was contained in a sturdy enamelled metal case. The controls featured an on-off switch combined with a calibration adjustment and a multi-position battery test switch.
  The batteries were contained within a clip-on cassette that took several minutes of careful preparation. A spare cassette was also pre-prepared to enable quick battery changes during operations.
  The meter was connected by a heavy duty cable to an ionisation chamber mounted onto a telescopic rod that was fed up a probe pipe in the ceiling of the monitoring post so that the probe was above ground. The top of the probe was protected by a polycarbonate dome that prevented fallout from entering the post.
caption: Fixed Survey Meter
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