GLOSSARY
PerkinElmer Life and Analytical Sciences 191
Color Quenching
Color quenching is the reduction in the scintillation intensity seen by the
photomultiplier tubes of a liquid scintillation counter due to the presence of
colored materials in the scintillation solution that interfere with the detection of
light. The result is fewer photons per keV of beta particle energy and usually a
reduction in counting efficiency.
CPM
Counts Per Minute. CPM are an expression of radionuclide activity. The gross
counts per channel cumulatively equal the counts per region. The gross counts
per counting region are divided by the count time to calculate CPM (Counts Per
Minute) for each region.
Curie (Ci)
A basic unit of radioactivity named for Marie and Pierre Curie, who discovered
Radium in 1898.
One Curie=3.7x10
10
Becquerels
One Becquerel=One Disintegration Per Second
Decay, radioactive
Decay is the spontaneous transformation of one nuclide into a different nuclide or
into a different energy state of the same nuclide. This process results in a
decrease over time of the number of original radioactive atoms in a sample. It
involves the emission from the nucleus of alpha particles, beta particles, gamma
rays or the nuclear capture or ejection of orbital electrons (fission). Also called
radioactive disintegration.
Delay Before Burst
This is the length of time after the initial pulse (prompt pulse) that the detector of
a liquid scintillation analyzer looks for additional pulses (afterpulses). Afterpulses,
which occur after the prompt pulse and delay time interval, indicate that a
scintillation event is due to background.
Delimited Text File
Mark this box to create a delimited text. Delimited Text is a file format in which
each data item is separated by a defined delimiting character. This is a common
format for transferring data between applications since database systems are able
to import and export this type of file.
Note:The field delimiter is defined by the Windows NT operating
system, using the L
IST SEPARATOR field on the NUMBER tab of the
R
EGIONAL SETTINGS PROPERTIES window accessed from the CONTROL
P
ANEL.
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