Radiation Flashcards
Non-ionizing radiation
Not enough energy to ionize water, heats it instead
Visible spectrum
360-700 nm
Infrared felt as ____
Heat
Depth of penetration is proportional to ___
Wavelength
Depth of penetration is inversely proportional to ___
Conductivity
Spectral power density
White/pink noise, broad/narrow band, pure tone
Radiance
Luminance, brightness, glare
Irradiance
Power density at the receiver, illuminance
Intensity
Power/energy density/per unit area
Free field
No obstructions between source and reciever
Alpha particle
He nucleus, 2 protons, 2 neutrons
Beta particle
electron
X-ray
Photon produced from bremsstrahlung (braking radiation) or electrons moving to another atomic orbital
Neutron
Neutron
Characteristic of Alpha particle
2+ charge, interactive, short penetration, stopped by paper
Characteristic of Beta particle
1- charge, limited penetration, stopped by aluminum foil
Characteristic of Gamma/x-ray particle
No mass/charge, highly penetrating, must use heavy/massive materials for shielding
How to shield from neutrons
Use low atomic number elements e.g. H, Be
3 factors of protection
Time, distance, shielding
Isotope
Same atomic number, different mass (i.e. different neutrons)
Half life
Time it takes for half of isotope atoms to disintegrate, isotopes characterized by decay/half life
Units of radioactivity
Curie, Becquerel
Units of absorbed dose
rad, gray
Linear energy transfer
energy loss per unit of path length (keV/um)
Particles with high and low LET
High: alpha, proton, neutron
Low: Beta, X, gamma
Dose equivalent units
Sievert/rem, regulatory limits based on rem or sieverts
