Geiger counter
Enable an AI agent to recognise a Geiger counter, assess whether its readings are usable for a stated task, and decide which measurements or maintenance actions are justified.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise a Geiger counter, assess whether its readings are usable for a stated task, and decide which measurements or maintenance actions are justified.
A Geiger-Müller counter is a gas-filled ionizing-radiation instrument operated on the Geiger plateau, in which each primary ionization in the tube triggers a self-limiting avalanche whose pulse height is essentially independent of deposited energy, so events are counted rather than spectroscopically resolved.
It can be Identify the installed Geiger-Müller channel and determine whether its documented response fits the intended measurement.; Configure supported counting modes, averaging intervals, probe settings and alarms under the applicable procedure.; Record timed counts or displayed readings together with background, geometry and instrument condition.; Compare repeat observations made under compatible conditions and flag unsupported comparisons.; Perform documented inspections and authorised functional checks, then classify task-specific readiness.; Flag suspect readings, restrict unsupported interpretations and refer failed or unsuitable equipment for service or replacement..
Distinguishing features
Documentation identifies a Geiger-Müller tube as the sensing element; clicks, a radiation symbol or a count display alone do not establish this.
The instrument detects and counts tube discharge events; distinguish it from an ionisation-chamber instrument whose measurement depends on collected ionisation current.
Its Geiger-Müller channel does not itself provide an energy-resolved spectrum for identifying radionuclides; distinguish this from a spectrometer or a hybrid instrument's separate spectroscopy channel.
An accumulated-dose display does not by itself establish suitability as a personal dosimeter; the documented intended use and performance must support that role.
Scope
+ Instrument identity and evidence that it uses a Geiger-Müller detector
+ Detector tube, probe window, shielding and supported radiation response
+ Power, configuration, functional checks and calibration applicability
+ Count observations and any instrument-derived dose-rate indications
+ Measurement geometry, background, timing and high-rate limitations
+ Task suitability, alarms and instrument-specific handling constraints
- Identity, composition and activity inventory of radioactive sources
- A person's accumulated exposure record or medical assessment
- Radiation transport and shielding design for a facility
- Site-wide radiation protection procedures and regulatory compliance
- Internal models of scintillation, semiconductor or ionisation-chamber instruments
- Radioactive material remediation and waste disposal operations
Characteristics
- Detection technology evidence
- Documented Geiger-Müller; documented hybrid; unverified Establishes whether this model applies and which sensing channel it describes.
- Installed detector and probe
- Instrument linked to tube or probe model, serial number where available, and connection Radiation response and calibration applicability depend on the actual detector configuration.
- Supported radiation response
- Documented radiation types and energy ranges, each with supporting evidence; unknown where unspecified Prevents assuming that every Geiger counter detects every relevant radiation type.
- Detector entrance and shielding configuration
- Window type and condition; cap, shutter or shield position; protective covering The material between the source and detector can change which radiation reaches the sensitive volume.
- Count observation
- Counts over a recorded interval in seconds; counts per second or counts per minute with averaging interval Preserves the observation needed to interpret statistical variation and compare measurements.
- Indicated dose rate
- Displayed value and unit, such as µSv/h, together with the stated dose quantity and conversion basis A dose-rate indication requires a supported relationship between detector response and the radiation field.
- Measurement geometry
- Detector-to-target distance in mm or cm, orientation, surveyed area and intervening materials Changes in placement can change the reading without any change in the target.
- Background reference
- Linked background observation with location, time, duration and detector configuration Supports defensible comparison between target readings and ambient counts.
- Measurement readiness
- Unchecked; ready for a specified task; restricted; failed; unknown, with evidence Combines relevant power, inspection, response-check and calibration evidence without treating power-on as proof of readiness.
- High-rate validity
- Within documented operating range; overload indicated; suspected saturation; unknown A low or stable display cannot establish a low radiation field when detector or electronics limitations may invalidate it.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 5 bundles · 9 layers · 16 findings · 31 questions.
Geiger detection identity Establishes which instrument and Geiger-Müller sensing configuration the model describes.
A product name or audible click is insufficient to establish detector technology or measurement capability.
Instrument and channel
Identifies the instrument and separates its Geiger-Müller channel from any other sensing functions.
Geiger-Müller channel evidence
Records the evidence needed to classify the device and identify the channel producing an observation.
- Which manufacturer document, marking or service record identifies the detector as a Geiger-Müller tube? provenance
- Does the device contain other detector technologies, and which channel supplies each displayed quantity? boundary
Probe and sensitive entrance
Connects detector identity to the physical path through which radiation reaches it.
Installed probe configuration
Records the tube or probe, its entrance window and the shielding or covers present during use.
- Which tube or probe is installed, and does the instrument configuration identify that probe correctly? definition
- What window, housing, cap, shutter or covering lies between the target and the detector's sensitive region? measurement
- Which radiation types and energy ranges are documented for this exact configuration? provenance
Response and interpretation Defines what each indication represents and the conditions under which it supports an inference.
Counts, dose-rate indications and radionuclide identification are different claims requiring different evidence.
Counting and dose conversion
Distinguishes observed events from quantities derived through instrument processing or calibration.
Displayed quantity basis
Records units, averaging and any conversion that connects counts to a displayed radiation quantity.
- Is the observation a timed total, count rate, dose rate or accumulated indication, and what interval or averaging setting applies? definition
- If dose units are displayed, what dose quantity, reference radiation and response correction support that indication? provenance
- Which intended conclusions require information that this counting channel cannot supply, such as radionuclide identity? boundary
Response limits
Captures conditions that can make an indication insensitive, biased or misleading.
Rate and field validity
Records the evidence needed to assess count losses, overload and applicability to the encountered radiation field.
- What usable count-rate range, dead-time behaviour and overload response are documented for this detector and electronics combination? provenance
- What observation or operating condition suggests that the reading may lie outside those limits? measurement
- When validity is uncertain, which interpretations must be withheld and which alternative measurement is required by the applicable procedure? action
Measurement and background Preserves the observation conditions needed to interpret and reproduce a Geiger-counter measurement.
A displayed number without counting time, background or detector placement cannot support a reliable comparison.
Target and geometry
Describes what was surveyed and how the detector was positioned or moved.
Survey placement
Records the target relationship, detector orientation and stationary or scanning measurement method.
- What target or location was measured, at what distance and orientation relative to the detector's sensitive region? measurement
- Was the probe stationary or scanning, and what dwell time, scan speed and coverage were recorded? measurement
- Which barriers, probe coverings or placement changes limit comparison with another observation? boundary
Background and variation
Connects target observations to background and the variation inherent in counting.
Count comparison evidence
Preserves gross observations and the evidence supporting any background subtraction or detection decision.
- What gross counts and acquisition duration were recorded for both the target and the background reference? measurement
- Were background and target observations obtained with compatible settings, geometry where relevant, and environmental conditions? boundary
- Which documented statistical method or task criterion determines whether the difference warrants a repeat measurement or further investigation? action
Readiness and use decisions Determines whether the configured instrument can support a particular task and what actions follow from its condition.
A functioning display does not establish detector response, applicable calibration or suitability for a proposed radiation measurement.
Functional and calibration evidence
Separates physical condition and response checks from calibration evidence.
Task readiness evidence
Records power condition, detector integrity, response-check results and calibration coverage for the installed configuration.
- What do the documented inspection and functional-check results show about the battery, probe window, cable, controls and detector response? measurement
- Which calibration record covers this instrument and probe, for which quantities and conditions, and does it meet the task's requirements? provenance
- Which failed, missing or inapplicable check prevents the instrument from being declared ready for this task? boundary
Alarms and handling
Connects indications and detector vulnerabilities to authorised operational actions.
Indication response and probe care
Records alarm meaning, response procedures and handling constraints that protect the probe and preserve measurement validity.
- Which quantity and threshold drive each alarm, and what procedure defines the required response? action
- What documented handling, protective-cover and cleaning restrictions apply to this probe and its window? provenance
- What action is required after suspected probe contamination, window damage, overload or failed response checking? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- End-window (typically mica) counters for alpha particles and low-energy beta
- Pancake-probe contamination monitors with a large thin window
- Thin-walled windowless tubes for high-energy beta and low-energy X/gamma
- Thick-walled steel tubes for gamma above about 25 keV
- Energy-compensated gamma dose-rate survey meters
- Halogen-quenched versus organic-quenched tubes
- Neutron-sensitive tubes (BF3 fill or boron lining)
- Pocket/personal GM monitors and civil-defense survey sets
- Which of these kinds and varieties hold for the sense of Geiger counter this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q48171 - Item for the instrument (Geiger-Müller counter); the tube is a distinct part
- HS / Harmonized System - 9030.10 - Complete instruments and apparatus for detecting or measuring ionizing radiation
- HTS (United States) - 8540.89.00 - Bare Geiger-Müller tubes classified as other gas-filled tubes
- IEC 81346-2 - BRE - Reference-designation class 'radiation counter'
- Philips / Centronic type code - ZP#### or MX### - Historical commercial GM-tube catalogue numbers (e.g. ZP1200 / MX146)
- Which of these identifiers and schemes hold for the sense of Geiger counter this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- IEC 60846-1:2009 - portable workplace and environmental ambient/directional dose-equivalent (rate) meters for beta, X and gamma (IEC SC 45B)
- IEC 60846-2:2015 - high-range portable emergency beta/photon dose and dose-rate meters (IEC SC 45B)
- IEC 60325:2002 - alpha, beta and alpha/beta surface-contamination meters and monitors (IEC SC 45B)
- IEC 60050-531 (IEC 50-531) - International Electrotechnical Vocabulary terminology used for GM tubes
- Which of these standards and regulation hold for the sense of Geiger counter this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Handheld workplace and environmental dose-rate surveys around nuclear plants, isotope labs, and medical radiation rooms
- Surface-contamination 'frisking' of hands, clothing, tools and waste with a pancake probe
- Civil-defense and emergency-response kits (historically the US CD V-700; still used by some volunteer and training programmes)
- Teaching-lab counting of alpha/beta sources where a loud click per event is the point
- Orphan-source and scrap-metal screening at yards and borders
- Consumer environmental monitoring sold as 'Geiger counters', especially after the 2011 Fukushima releases
- Which of these real-world use hold for the sense of Geiger counter this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Count rate (observed pulses) - background about 0.1-1; saturates above a few thousand - s^-1
- Ambient dose equivalent rate H*(10) on portable GM survey meters - about 0.01 µSv/h to 50 mSv/h on many handheld units; natural background typically 0.05-0.2 µSv/h - µSv/h
- Tube operating voltage on the Geiger plateau - about 400-1200 - V
- Dead time / recovery after a pulse - about 100-1000 (typically a few hundred) - µs
- End-window areal density (mica) - about 1.5-2.0 - mg/cm²
- Fill-gas pressure - a few tenths of an atmosphere - atm
- Intrinsic gamma detection efficiency of a steel-walled tube - about 1 over a wide energy range - %
- Which of these typical measurements hold for the sense of Geiger counter this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Dead-time paralysis at high rates: the meter can under-read, even toward zero, in a field that should peg the scale
- Organic quench gas is consumed; alcohol-quenched tubes wear out and then go into continuous discharge or stop counting
- Thin mica windows puncture easily, dumping fill gas and killing the tube
- Pulse height carries no energy or particle-type information, so a count rate can be mistaken for a dose or an identified isotope
- Uncompensated tubes have a strongly energy-dependent gamma response and can mis-state H*(10)
- Overvoltage produces continuous discharge; undervoltage drops off the plateau and under-counts
- Glass envelopes are mechanically fragile; halogen fill is chemically aggressive to some electrode metals
- Which of these failure modes and hazards hold for the sense of Geiger counter this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- In German technical use, Geigerzähler or Auslösezählrohr names the tube; everyday Geigerzähler often means any complete radiation meter
- In US civil defense, 'Geiger counter' is a colloquial name for any handheld radiological survey meter; many issued CD instruments were ionization chambers, not GM tubes
- US field practice still often reports mR/h; Europe and post-Fukushima consumer meters almost always display µSv/h
- UK operational language splits 'contamination monitor' (pancake/frisker) from 'dose-rate meter', even when both use GM tubes
- Japan saw a large consumer GM-meter market after 2011, with public discussion framed in µSv/h rather than counts
- Which of these regional variation hold for the sense of Geiger counter this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Proportional counter - Pulse height scales with energy deposited and can discriminate alpha from beta; a GM pulse is essentially the same size for every event
- Ionization-chamber survey meter - Collects charge without a Geiger avalanche, so it stays linear at high dose rates where a GM tube is dead or paralyzed
- Scintillation survey meter - Converts energy to light and can retain energy information with microsecond-scale dead time; a GM tube cannot spectroscopically resolve events
- Civil-defense ion-chamber 'Geiger' (high-range CD sets) - Same colloquial name and yellow box, but no GM tube: look for a sealed ion chamber and a high R/h scale rather than a thin-window probe and clicker
- Which of these neighbouring kinds and how to tell them apart hold for the sense of Geiger counter this model covers, and on what evidence? provenance
Sources
- Geiger counter - Instrument definition, end-window/pancake/windowless kinds, neutron variant, and typical survey uses
- Geiger-Müller tube - Tube constructions (end-window, pancake, thick-walled, thin-walled) and wall-thickness practice
- Geiger counter (Q48171) - Wikidata identifier, aliases (Geiger-Müller counter), inception 1928, and that the instrument has a Geiger-Müller tube as a part
- IEC 60846-2:2015 Radiation protection instrumentation - Ambient and/or directional dose equivalent (rate) meters and/or monitors for beta, X and gamma radiation - Part 2 - IEC performance standard for portable emergency dose-rate meters; points to IEC 60846-1 and IEC 60325 for workplace meters and contamination probes
- IEC 60325:2002 Radiation protection instrumentation - Alpha, beta and alpha/beta (beta energy > 60 keV) contamination meters and monitors - IEC requirements for surface-contamination meters of the kind that commonly use pancake GM probes
- Philips Geiger-Müller Tubes (T06 databook, June 1986) - Manufacturer definition of a GM tube, ZP/MX type-code scheme, terminology pointing to IEC 50-531, and typical dose-rate ranges of commercial tubes
- Geiger Counter - Geiger-Mueller Detector - End-window versus windowless practice, mica window areal density, alpha air-gap constraint, and ~1% gamma efficiency of steel-walled tubes
- What is Geiger Counter vs Proportional Counter - Lack of energy/type discrimination, dead-time limitation, and the contrast with proportional counters
- Civil defense Geiger counters - Colloquial US/UK naming, CD V-700 as a true GM set, saturation under-reading, and that many 'Geiger' civil-defense meters were ion chambers
- Zählrohr - German naming (Geigerzähler, Auslösezählrohr) and that 'Zählrohr' can mean ionization chamber, proportional, or GM depending on operating region
What the second pass must settle
- Should the registry entry include bare Geiger-Müller detector modules, or only instruments that provide counting and an accessible indication?
- How should hybrid instruments link this model to separate detector-channel models without duplicating the physical instrument's identity?
- Which manufacturer documents establish radiation response, dead time, overload behaviour and dose-conversion limits for the instrument variants to be represented?
- Which task-specific procedures supply acceptable calibration evidence, functional-check criteria and rules for interpreting differences from background?
- What evidence is required before a particular Geiger counter can support surface-activity estimates or personal-dose tracking beyond recording its displayed values?