Uploaded February 2026 | Updated September 2026, 1 week ago

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Introduced in 1955 by Fisher Research Laboratories of Palo Alto, California, the Count-O-Scope was a beta/gamma Geiger counter designed for performing radiometric grid surveys. It used a Victoreen 1B85 detector tube and incorporated a linear rate meter and mechanical scaler (counter) to automatically count the number of particles detected within a 30 or 60 second period.

Geiger Counters video: youtu.be/iPMiG2fxBYg
CAE 1002 Gammascint video: youtu.be/nNGSm3jieIM
Cold War Radiation Detectors video: youtu.be/XZX_T4QVUrE
Civil Defence Radiation Detectors videos: youtu.be/faJLf_k9UrI
CD 717 Gamma Survey Meter video: youtu.be/maWRvegUzqk:

0:00 Introduction
0:53 History of Fisher Labs
3:08 Early Fisher M-Scopes
6:56 Case and Accessories
8:40 Victoreen 1B85 Detector Tube
10:05 Controls and Readouts
11:45 Batteries
12:34 Circuit Analysis
16:18 Later Fisher Lab History
17:24 Outro

SOURCES
national-radiation-instrument-catalog.com/new_page_6.htm
orau.org/health-physics-museum/collection/geiger-mueller-tubes/victoreen-model-1b85-gm-tube.html
orau.org/health-physics-museum/collection/survey-instruments/mid-to-late-1940s/fisher-m-scope.html
orau.org/health-physics-museum/collection/survey-instruments/mid-to-late-1940s/fisher-m-scope-c-12-geiger-counter.html
orau.org/health-physics-museum/collection/survey-instruments/mid-to-late-1940s/fisher-m-scope-c-18-geiger-counter.html
orau.org/health-physics-museum/collection/survey-instruments/1950s/fisher-uranium-scout.html
mhs.mb.ca/docs/sites/endertonbuilding.shtml
fisher-impulse.com/about
patents.google.com/patent/US2066561A/en
lampes-et-tubes.info/rd/1B85.pdf