28.4
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28.4Radiation in Your Life
Ionizing Radiation Radiation with enough energy to knock
electrons off atoms and produce ions X-rays and radiation emitted by radioisotopes
are ionizing radiation Not detectable by senses Geiger counter detects this type of radiation
Geiger counter Used to detect beta radiation Radiation enters gas filled tube and creates
ions which conduct electricity Bursts of current creates audible clicks or
starts electronic counter
Scintillation counter Device with a surface coated with phosphor Ionizing radiation causes the phosphor to
“flash” when it hits it Number of flashes is detected electronically TV screens use ZnS as the phosphor and
electrons are shot at the screen . The scintillations produce a pattern which is the picture we see
Film Badges Several layers of photographic film covered
with black, lightproof paper Badges are worn by people who work near
radiation sources and are developed at specific intervals
Used to detect how much radiation a person is exposed to
Radiation Uses Used to detect trace amount of elements by
neutron activation Neutron activation can be used in forensics-
to detect art forgeries, and analyze gunpowder Radioactive isotopes can be used to trace
where elements go- as in chemical reactions Radioactive tracers can trace where
substances travel
Radiation Uses Radioisotopes can help diagnose disease- I-131 helps diagnose thyroid problems;
technetium-99 diagnoses brain tumors and liver problems; P-32 used for skin cancer
Radiation is used to treat cancer; Co-60 and Cs-137 ; often gamma sources are used- c ancers are more susceptible to high energy radiation
Radiation Uses Salts of radiactive isotopes can be sealed in
gold tubes and directly implanted in tumors- emit beta or gamma