Page 10 - Radiation Safety

ENVIRONMENTAL MONITORING

c) Exactness/Linearity
f) Energy Dependence Maintenance
- Deviation of measured dose Response proportional to the
to the true value by a check energy & activity - Smooth surface
source - Material
- Easy to decontamination
b) Repeatability e) Instrument ResponseTime h) Effect of Mixed Radiation
- Small standard deviation to - Determine equipment - Instrument responses to only Battery
stabilization
one type of radiation at a time
the average value
- Light, low cost, long life
a) Radiation Quantity d) Measurement Range g) Isotropy & Geotropism
- Dose given must be Capability to detect radiation - Relative response at every Design
equivalent to organ /
effective dose. within expected range angles & orientations - Small, light, rugged, convenient
Radiological Characteristic Condition of Use
Characteristic
Application of Calibration
Factor (CF)
Choice/Selection SURVEY METER
D = B x CF x J
D = Actual/true Reading
a) Sealed Source B = Meter Reading
CF = Calibration Factor
- Based on Energy Calibration J = Correction Factor for scale
non-linearity
Low Energy : Ionization
Chamber High Energy:
Geiger Muller (GM)
Requirement of Calibration Requirement of Recalibration
b) Unsealed Source i. To comply with legal requirement i. To comply with license requirement
Environmental Sample : ii. Ensure working properly and function reliably ii. To confirm the performance after maintenance/
Thin Window GM repair
iii. Estimate error, to improve overall accuracy
Surface Contamination : iii. To ensure its consistency and reliability
Thin window GM, iv. Equipment traceability
Proportional or Scintillation v. In case of emergency, the equipment can be iv. To confirm if a survey meter gives suspicious
count
loaned to other company
v. To extend the application if a meter used beyond
the scope of calibration.