2.1 What Radiation and Radioactivity Are
7
Table 2.1 Information about alpha radiation
What will emit alpha radiation • Nuclides with high atomic number and high atomic mass (e.g.
Am-241, Ra-226, U-235, etc.)
• Smoke detectors, gas lantern mantles, welding rods, some
rocks, nuclear weapons, some radioactive sources
Detectors and instruments
• Geiger Mueller “pancake” probes, alpha probes
Health effects
• Some alpha emitters are also toxic heavy metals (e.g.
uranium)
• No health effects from external alpha radiation
• Can be very harmful if inhaled or ingested
Protective equipment
• Respiratory protection if activity is airborne
• Cover open cuts, scrapes, and other wounds, gloves
Levels of concern a
• Greater than 10,000 cpm on the ground
• Greater than 1000 cpm on the bare skin
• Airborne alpha activity
Other comments
• Some alpha emitters (e.g. Am-241, Ra-226) also emit gamma
radiation
• The former Russian spy Alexander Litvenenko was killed by
adding trace amounts of alpha-emitting polonium to tea
a Note that readings in Tables 2.1, 2.2 and 2.3 are given in cpm (what the instrument reads) and not
in dpm (the activity that is actually present) to simplify comparison with the instrument being used.
The count rates provided here are for a “pancake” type GM detector at a distance of about 2 cm
from the surface being surveyed. Other detectors will produce different readings
Table 2.2 Information about beta radiation
What will emit beta radiation • Any element can have beta-emitting nuclides
• Many laboratory nuclides (e.g. H-3, C-14, P-32, S-35)
• Newer self-luminous watch dials and some self-illuminating
exit signs
Detectors and instruments
• Geiger counters (e.g. GM pancake probe)
• Beta scintillation probes
• Liquid scintillation counter (in the laboratory)
Health effects
• External beta radiation cannot expose internal organs
• May cause shallow burns (beta burns) if bare skin is
contaminated
• Can expose internal organs if inhaled or ingested
Protective equipment
• Anti-contamination clothing (including heavy gloves if
possible) to reduce skin contamination
• Respiratory protection (if airborne)
• Cover open cuts, scrapes, or wounds
Levels of concern*
• Greater than 100,000 cpm on the ground
• Greater than 10,000 cpm on the skin
Other comments
• Many beta-emitters also emit gamma radiation (e.g. I-131)
• There have been several instances of laboratory workers trying
to poison co-workers with beta-emitters such as P-32
• Positron emission will be accompanied by 511 keV gamma
radiation from electron–positron annihilation
*See comment to Table 2.1
7
Table 2.1 Information about alpha radiation
What will emit alpha radiation • Nuclides with high atomic number and high atomic mass (e.g.
Am-241, Ra-226, U-235, etc.)
• Smoke detectors, gas lantern mantles, welding rods, some
rocks, nuclear weapons, some radioactive sources
Detectors and instruments
• Geiger Mueller “pancake” probes, alpha probes
Health effects
• Some alpha emitters are also toxic heavy metals (e.g.
uranium)
• No health effects from external alpha radiation
• Can be very harmful if inhaled or ingested
Protective equipment
• Respiratory protection if activity is airborne
• Cover open cuts, scrapes, and other wounds, gloves
Levels of concern a
• Greater than 10,000 cpm on the ground
• Greater than 1000 cpm on the bare skin
• Airborne alpha activity
Other comments
• Some alpha emitters (e.g. Am-241, Ra-226) also emit gamma
radiation
• The former Russian spy Alexander Litvenenko was killed by
adding trace amounts of alpha-emitting polonium to tea
a Note that readings in Tables 2.1, 2.2 and 2.3 are given in cpm (what the instrument reads) and not
in dpm (the activity that is actually present) to simplify comparison with the instrument being used.
The count rates provided here are for a “pancake” type GM detector at a distance of about 2 cm
from the surface being surveyed. Other detectors will produce different readings
Table 2.2 Information about beta radiation
What will emit beta radiation • Any element can have beta-emitting nuclides
• Many laboratory nuclides (e.g. H-3, C-14, P-32, S-35)
• Newer self-luminous watch dials and some self-illuminating
exit signs
Detectors and instruments
• Geiger counters (e.g. GM pancake probe)
• Beta scintillation probes
• Liquid scintillation counter (in the laboratory)
Health effects
• External beta radiation cannot expose internal organs
• May cause shallow burns (beta burns) if bare skin is
contaminated
• Can expose internal organs if inhaled or ingested
Protective equipment
• Anti-contamination clothing (including heavy gloves if
possible) to reduce skin contamination
• Respiratory protection (if airborne)
• Cover open cuts, scrapes, or wounds
Levels of concern*
• Greater than 100,000 cpm on the ground
• Greater than 10,000 cpm on the skin
Other comments
• Many beta-emitters also emit gamma radiation (e.g. I-131)
• There have been several instances of laboratory workers trying
to poison co-workers with beta-emitters such as P-32
• Positron emission will be accompanied by 511 keV gamma
radiation from electron–positron annihilation
*See comment to Table 2.1