cadmium tungstate
Enable an AI agent to recognise cadmium tungstate, assess the condition and suitability of a particular material lot, and determine what handling, testing or use is justified by available evidence.
Bundle → Layer → Finding → Questions Filled
5 bundles · 9 layers · 15 findings · 23 questions
Compound identity and composition Establish what makes a specimen cadmium tungstate and which compositional qualifications apply.
Identity and phase evidence
Connect the registered name to chemical and phase-sensitive evidence.
Cadmium tungstate identification
Record the evidence supporting CdWO4 identity and distinguish it from other tungstates and precursor mixtures.
- Which analytical evidence establishes CdWO4 rather than merely the presence of cadmium, tungsten and oxygen? definition
- Which authoritative records verify the CAS, PubChem and EC identifiers, and do their identity boundaries match this material? provenance
Lot composition qualifications
Describe compositional differences that can affect interpretation and use.
Purity, dopants and isotopes
Keep measured impurities, deliberate additions and isotope specifications attached to the material lot.
- What purity, Cd:W ratio and impurity concentrations were measured, using which methods and detection limits? measurement
- Are dopants or isotope enrichment specified, and what compositional change would place the specimen outside the cadmium tungstate identity boundary? boundary
Crystal form and condition Represent the material's phase constitution, morphology and current physical condition.
Structure and morphology
Describe crystal structure and physical form through specimen-specific observations.
Phase, crystallinity and form
Record identified phases, crystallinity, orientation where relevant, and dimensions or particle sizes.
- Which crystal structure and secondary phases are supported by diffraction or other phase-sensitive measurements at the recorded conditions? measurement
- Is the specimen powder, polycrystalline material or a single crystal, and which dimensions, particle sizes or crystal orientations matter for its use? boundary
Integrity and state changes
Track defects and changes following processing, storage or exposure.
Damage and thermal history
Attach cracks, inclusions, surface changes and thermal observations to the specimen and its history.
- What cracks, inclusions, discoloration or surface contamination are observed, and how were they assessed? measurement
- Which measured thermal or chemical changes constrain further heating, annealing, cutting or polishing of this lot? action
Optical and scintillation qualification Connect material measurements to an explicitly defined optical or radiation-detection use.
Optical transport
Assess how the specimen transmits light across relevant wavelengths and paths.
Transmission and optical condition
Record wavelength-dependent transmission and separate material effects from geometry and surface preparation.
- What transmission or absorption spectrum was measured, with what path length, temperature, orientation and surface finish? measurement
- Which observed losses are attributable to the cadmium tungstate specimen, and which arise from coatings, coupling or measurement optics? boundary
Radiation response
Characterise scintillation output and temporal response under explicit excitation and readout conditions.
Scintillation performance evidence
Record light yield, emission spectrum, decay behaviour and any measured afterglow without treating detector results as universal material constants.
- What light yield, emission spectrum, decay components and afterglow were measured for which radiation type, energy and temperature? measurement
- Which reference standard, readout calibration and acceptance criteria justify using this lot in the intended detector? action
Handling, processing and end of life Link material form and proposed operations to verified exposure controls and disposition requirements.
Hazard and operation evidence
Determine which hazard information and controls apply to the actual form and proposed operation.
Cadmium-related handling constraints
Connect the material's safety documentation to handling intact crystals, powders and processing residues.
- Which current safety data sheet and jurisdiction-specific classification apply to this cadmium tungstate lot and physical form? provenance
- What exposure limits and controls apply when the proposed operation can generate cadmium-containing dust, slurry or heated emissions? action
Storage, recovery and disposal
Maintain containment and determine acceptable destinations for material and residues.
Material and residue disposition
Treat unused material, broken crystals, powders and polishing residues according to their documented composition and contamination.
- Which storage conditions, segregation requirements and container practices are supported by the applicable material documentation? action
- Which authorised recovery or disposal route accepts the specific cadmium tungstate material or residue, including any additional contamination? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Check these first
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these check these first hold for the sense of cadmium tungstate this model covers, and on what evidence? provenance
Kinds and varieties
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these kinds and varieties hold for the sense of cadmium tungstate this model covers, and on what evidence? provenance
Identifiers and schemes
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these identifiers and schemes hold for the sense of cadmium tungstate this model covers, and on what evidence? provenance
Real-world use
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these real-world use hold for the sense of cadmium tungstate this model covers, and on what evidence? provenance
Typical measurements
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these typical measurements hold for the sense of cadmium tungstate this model covers, and on what evidence? provenance
Failure modes and hazards
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these failure modes and hazards hold for the sense of cadmium tungstate this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Recalled without web access and unsourced; every item is a lead to verify.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of cadmium tungstate this model covers, and on what evidence? provenance
Classifiers Filled
- Family
- Thing Registry
- Category
- Physical world and living systems
- Entry kind
- thing
- Plane
- PHY
- Domain
- PHY.MAT
What it is Filled
Cadmium tungstate (CdWO4) is a crystalline inorganic compound of cadmium, tungsten and oxygen that adopts the monoclinic wolframite structure under ambient conditions and is used as a scintillator for detecting ionizing radiation.
In scope
- Chemical identity and evidence that the material is cadmium tungstate, CdWO4
- Purity, stoichiometry, impurities, dopants and isotopic composition of identified lots
- Phase, crystallinity, physical form and changes in material condition
- Optical and scintillation performance under recorded test conditions
- Evidence governing handling, storage, processing and disposal of the cadmium-containing material
Out of scope
- Complete radiation detectors, scanners and their system-level performance
- Crystal-growth equipment and manufacturing-process models
- Other cadmium compounds, other tungstates and physical mixtures of precursor materials
- General radiation-field descriptions and radiation-source operation
- Clinical outcomes, occupational disease and jurisdiction-wide regulatory frameworks
Why it exists Filled
Enable an AI agent to recognise cadmium tungstate, assess the condition and suitability of a particular material lot, and determine what handling, testing or use is justified by available evidence.
Distinguishing features Filled
- Require evidence for the CdWO4 compound identity; detecting cadmium, tungsten and oxygen together does not establish that they form cadmium tungstate.
- Use phase-sensitive evidence to distinguish cadmium tungstate from a mixture of cadmium-bearing and tungsten-bearing compounds.
- Confirm the cadmium constituent when distinguishing this material from calcium tungstate, zinc tungstate or other tungstate scintillators.
- Separate intrinsic material evidence from measurements of a packaged detector whose readout, geometry and optical coupling influence the result.
- Distinguish nominally identical lots by purity, dopants, isotope composition and crystal quality before treating their performance as interchangeable.
What robots and AI may and may not do Filled
Must not
- Cut, grind or polish the crystal without dust controls and protection required for cadmium compounds.
- Dispose of detector crystals or cadmium waste in ordinary refuse or drains.
- Sell or recycle detectors containing it without disclosing the cadmium content.
- Present a faulty detector as calibrated.
Only with a human decision
- Approving decommissioning or disposal of detectors containing it.
May
- Describe cadmium tungstate as a scintillator crystal used in radiation detectors.
- Report hazards and handling rules for cadmium compounds from safety data sheets.
Moral aspects Filled
- Cadmium is toxic and persistent and harms kidneys and bones.
- Radiation detectors protect people; their reliability matters.
Who is affected
- Detector manufacturers' workers
- Waste and recycling workers
- Patients and staff relying on detectors
Owners Filled
Steward
The laboratory or business that holds it; chemical safety authorities regulate supply and use.
Links to other meta-models Filled
parent
- Q11173 - registry parent class
What else AI and robots need to interact with it Filled
Identity and identifiers required Filled
- Vercy registry: vr.tr.cadmium-tungstate
- Wikidata: Q1969116 (https://www.wikidata.org/wiki/Q1969116)
Direct properties required Filled
- Chemical identity: CdWO4; independently verified registry identifiers and identity evidence
- Composition and purity: Cd:W:O atomic ratios; purity in mass percent; impurity concentrations in mg/kg with detection limits
- Dopant and isotope specification: Declared dopants and concentrations; elemental isotope fractions; unspecified status
- Phase and crystallinity: Identified phases, phase fractions where measured, single-crystalline or polycrystalline state, and supporting method
- Physical form and integrity: Powder, granules or crystal; dimensions or particle-size distribution in specified units; cracks, chips and surface condition
- Optical transmission: Transmission percent versus wavelength in nm, with optical path length in mm and temperature in K
- Scintillation response: Light yield in photons/MeV or an explicitly defined relative scale; emission wavelength in nm; decay components in ns or µs
- Thermal behaviour: Observed transitions or decomposition in °C or K, with atmosphere, pressure and measurement method
- Handling and disposal evidence: Applicable safety data sheet, classification source, local handling procedure and waste determination
Recognition required Filled
- A transparent, colourless to pale yellow dense crystal, often cut into blocks or arrays.
- Usually mounted inside a detector housing coupled to a light sensor.
Capabilities and actions required Filled
- Identify a candidate lot through composition and phase evidence.
- Compare lots for an intended optical or scintillation application using measurements with compatible conditions.
- Select characterisation needed to resolve uncertain purity, crystal quality or performance.
- Assess whether cutting, polishing, grinding or heating is supported by material-specific procedures and hazard evidence.
- Track contamination, physical damage or performance changes and decide whether a lot needs requalification.
- Route material and processing residues to an evidenced recovery or disposal pathway.
Hazards and failure modes required Filled
- Cadmium exposure from dust during machining.
- Environmental contamination from improper disposal.
- Cracked crystals degrading detector performance.
Standards and interfaces required Filled
- Globally Harmonized System of Classification and Labelling of Chemicals (GHS), United Nations.
Context of use required Filled
- Cadmium tungstate is encountered as a scintillating crystal in instruments that detect X-rays and gamma rays.
- It converts absorbed radiation energy into light that a coupled optical detector can measure.
- Material assessment considers crystal quality, optical transmission and suitability for the intended detector.
Sources Filled
- Wikidata item Q1969116: cadmium tungstate - identity and sense of the item
- Wikipedia: Cadmium tungstate - general description of the item
Open questions
- Which authoritative identity records establish the correct CAS, PubChem and EC identifiers and their coverage of doped or isotopically enriched cadmium tungstate?
- Which reference measurements establish crystal structure, density and thermal behaviour, and under what conditions do reported transitions represent melting, decomposition or another change?
- What application-specific purity, impurity and crystal-defect thresholds support meaningful cadmium tungstate grade distinctions?
- Which comparable primary measurements establish scintillation yield, emission, decay, afterglow and stability, including intrinsic radioactive background where relevant to the intended use?
- Which current hazard classifications, exposure limits and waste requirements apply to cadmium tungstate in each intended jurisdiction and physical form?
Machine files
Provenance
thing registry research (pass 2) · unreviewed
Built from: models/things/publications/thing-q1969116/spec.json