Definitions Flashcards
ALARA
As Low as Reasonably Achievable
Radiation Protection (3 main factors)
Time / Distance / Shielding
Particulate Radiation
High speed particles
Electromagnetic Radiation
Neither mass nor charge, but have energy (both x & gamma rays are electromagnetic only differ in origin)
Radioactive
Unstable isotopes
(+) Alpha Particle Emission
Heavy, stable particle ejected from nucleus @ extremely high velocity (continues to occur until stable element is reached)
Neutron Emission
Decay by fission; splits into 2 smaller nuclei
(-) Particulate Radiation
Beta particle emission is dependent on “N” to “Z” ratio
Radiation
High speed particles or energy travelling in electromagnetic waves
Main difference between various forms of electromagnetic energy is _________&_________.
Frequency & Wavelength
non-ionizing = longer/slower) (ionizing = shorter higher
Ionization
Process of adding electrons to or removing electrons from atoms or molecules
Exposure
Quantity of radiation incident upon an object (R)
Radiation Intensity (Dose Rate)
Absorbed by any matter placed in a radiation beam (R/hr or Sv/hr)
Radiation Absorbed Dose
Radiation damage in living tissue (RAD or Gray Gy)
Quality Factor
Biological effectiveness
Half Life
Length of time required for the activity to decay to one-half its initial activity
Types of Survey Meters
- Ion Chamber Instruments
- Geiger muller counter
- Proportional counters
Types of Dosimeters
- DRD - direct reading dosimeter
- TLD - thermoluminescent dosimeter
- OSL - optically stimulated luminescence dosimeters
Classification of Effects (4)
- Acute - within mins/days/weeks
- Chronic - years or generations later
- Somatic - rad injury to person but not reproductive cells
- Genetic - exposure that results in chromosome damage
Collimator
Small pcs of lead, depleted uranium or tungsten that partially surrounds source to absorb radiation not directed toward area being RT’d
Half Value Layer
Reduce intensity to one half of its original value
Tenth Value Layer
Reduce intensity to one tenth of its original value
Absorbed Dose
Radiation has been absorbed by some substance; usually human tissue
Attenuation
Reduction in intensity of radiation as it passes through any material ie. lead shielding
Background Radiation
Radiation emitted from naturally occurring radioactive materials in earth & from cosmic rays
Activity
Strength of radioactive source
Collimator
Small radiation shield of lead or other heavy material (place on the end of guide tube)
Decay
Disintegration of atoms that have excess energy; radiation emitted in process
Isotopes
Same element w/ different mass; emits Alpha & Beta Particles
Xray
Transfer of energy between high speed interaction of electrons & dense target material & can be controlled (on/off switch)
Gamma
Atom or molecule which has charge due to loss or gain of valence
Ionization
Process of adding electrons to or removing electrons from atoms or molecules
