How the Geiger Counter Detects Invisible Radiation
A 1947 patent for a radiation detection device that uses a gas-filled tube to identify and count high-energy particles.
Original patent title: “Geiger counter”
A 1947 patent for a radiation detection device that uses a gas-filled tube to identify and count high-energy particles. Granted to International Standard Electric Corp in 1949 with 6 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
The device functions by using a sealed tube filled with a specific gas at low pressure. When a radioactive particle enters the tube, it ionizes the gas, creating a brief electrical pulse between the electrodes. This pulse is then amplified and recorded as a 'click' or a numerical count, providing a direct measurement of radiation levels in the immediate environment.
The gap
What does this patent NOT cover?
- Does not cover solid-state radiation detectors like silicon diodes
- Does not cover scintillation counters that use light-emitting crystals
- Does not cover the fundamental physics of ionization itself
- Does not cover digital signal processing or modern computer-based data analysis
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The invention refined the gas-discharge mechanism to ensure that even a single ionizing event could trigger a measurable, distinct electrical pulse, effectively turning invisible radiation into audible or visual data.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Handheld radiation survey meters
Laboratory contamination monitors
Geiger-Muller tubes in nuclear research
Why it matters
The bigger picture
This technology was essential for the nuclear age, allowing scientists and workers to safely monitor radioactive materials. It became the standard tool for everything from geological surveying to medical safety and nuclear research.
Filed
February 1, 1947
Granted
October 25, 1949
Market context
Who's building on this
Companies in this space
Modern manufacturers like Thermo Fisher Scientific and various specialized nuclear instrumentation companies continue to refine the sensitivity and portability of gas-filled radiation detectors.
Market impact
This patent helped standardize the design of portable radiation detection, enabling the growth of the nuclear power industry and safety protocols for handling radioactive isotopes in medicine and research.
Claim 1 — Plain English
What this patent covers
The device functions by using a sealed tube filled with a specific gas at low pressure. When a radioactive particle enters the tube, it ionizes the gas, creating a brief electrical pulse between the electrodes. This pulse is then amplified and recorded as a 'click' or a numerical count, providing a direct measurement of radiation levels in the immediate environment.
The clever bit
The invention refined the gas-discharge mechanism to ensure that even a single ionizing event could trigger a measurable, distinct electrical pulse, effectively turning invisible radiation into audible or visual data.
What it does not cover
- Does not cover solid-state radiation detectors like silicon diodes
- Does not cover scintillation counters that use light-emitting crystals
- Does not cover the fundamental physics of ionization itself
- Does not cover digital signal processing or modern computer-based data analysis
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Limited data
Citation count
17/40
Early citations
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$7K – $23K
Midpoint $14K · expired or expiring · industry ×1.5
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Concepts involved
Citations
Patent lineage
Cite this patent
Ladislas, G. (1949). How the Geiger Counter Detects Invisible Radiation (U.S. Patent No. 2,485,586). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2485586/geiger-counter
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How the Geiger Counter Detects Invisible Radiation cover?
A 1947 patent for a radiation detection device that uses a gas-filled tube to identify and count high-energy particles.
Who owns patent US 2485586?
International Standard Electric Corp owns this patent, granted in 1949.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 2485586 cited by?
This patent has been cited by 6 later patents that build on its ideas.
What problem does this patent solve?
This technology was essential for the nuclear age, allowing scientists and workers to safely monitor radioactive materials. It became the standard tool for everything from geological surveying to medical safety and nuclear research.
What does this patent NOT cover?
Does not cover solid-state radiation detectors like silicon diodes
Same assignee
More from International Standard Electric Corp
Patent monitoring