roentgen (unit)
E416996
The roentgen is an obsolete unit of exposure to ionizing X- or gamma radiation, historically used to quantify the amount of radiation that produces a specific level of ionization in air.
All labels observed (1)
| Label | Occurrences |
|---|---|
| roentgen (unit) canonical | 1 |
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
non-SI unit
ⓘ
obsolete unit ⓘ unit of radiation exposure ⓘ |
| approximateRelation | 1 R ≈ 0.00877 Gy in soft tissue (historical rule of thumb) ⓘ |
| category | units named after people ⓘ |
| chargePerMass | 2.58×10⁻⁴ C/kg of air ⓘ |
| classification | cgs electrostatic unit-based measure ⓘ |
| definedBy | amount of ionization produced in air ⓘ |
| definedInTermsOf | electric charge per unit mass of air ⓘ |
| definitionCondition |
dry air
ⓘ
standard temperature and pressure ⓘ |
| dimension | electric charge per mass ⓘ |
| etymology | derived from surname Röntgen ⓘ |
| field |
health physics
ⓘ
medical physics ⓘ nuclear engineering ⓘ |
| governingBody | International Commission on Radiation Units and Measurements ⓘ |
| historicalDefinition | 1 electrostatic unit of charge per cubic centimeter of air ⓘ |
| introduced | 1928 ⓘ |
| introducedBy |
International Commission on Radiation Units and Measurements
ⓘ
surface form:
International Commission on Radiological Units
|
| measurementContext |
film badge dosimetry (historical)
ⓘ
ionization chambers ⓘ |
| medium | air ⓘ |
| namedAfter |
Wilhelm Röntgen
ⓘ
surface form:
Wilhelm Conrad Röntgen
|
| notEqualTo |
absorbed dose in tissue
ⓘ
dose equivalent ⓘ |
| quantityMeasured | exposure to ionizing radiation ⓘ |
| radiationType |
X-rays
ⓘ
gamma rays ⓘ |
| regulatoryStatus | discouraged in modern standards ⓘ |
| relatedQuantity |
absorbed dose
ⓘ
air kerma ⓘ |
| relatedUnit |
gray
ⓘ
sievert ⓘ |
| replacedBy | coulomb per kilogram ⓘ |
| safetyUse | calibration of early radiation instruments ⓘ |
| scope | exposure in air only ⓘ |
| spellingVariant |
roentgen
ⓘ
röntgen ⓘ |
| status | superseded by SI units ⓘ |
| symbol | R ⓘ |
| usedHistoricallyIn |
Europe
ⓘ
Soviet Union NERFINISHED ⓘ United States of America ⓘ
surface form:
United States
|
| usedIn |
radiation dosimetry
ⓘ
radiation protection ⓘ radiology ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.