ORTEC RADEAGLET, User Manual

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A Glossary
The glossary contains key technical terms used throughout this manual.
Background The term background refers to the ambient radiation present around the instrument. The
background includes
Þ
Natural background and mixtures of perturbation sources surrounding the
measurement site. Situations may arise, where the reduction of perturbation sources cannot be
optimal, e.g. in laboratories operating with radiation sources.
Centroid Center of a peak. The centroid is used to measure peak position. Its numerical value is often
generated by a peak fit routine. In the RADEAGLET, a peak fit is performed in the CHECK-CAL
screen, presenting you the centroid and resolution of the peak.
Full-width-at-half-maximum (FWHM) There are two points of the peak which have a height that equals
half the height of the centroid position. One point on the left, another one right of the centroid.
The distance between the energies of these two points is called the full-width-at-half-maximum
abbreviated as FWHM. The FWHM divided by the centroid energy leads to the resolution.
Geiger-Müller Detector (GM) Secondary detector onboard the RADEAGLET. The GM detector consists
of a pressurized tube filled with a radiation sensitive gas. Various gases can be used here, typically
inert gases such as helium, argon, neon or xenon. Often these are mixed with an organic vapor
or a halogen gas. GM tubes detect radiation utilizing an anode-cathode pair inside this gas. The
cathode is the tube housing while the anode is a small wire in the center of the chamber. Radiation
ionizes the atoms of the gas initiating a charge avalanche which drives a current towards the anode
which generates a count. The number of counts is proportional to the strength of the radiation.
GM detectors are non-spectroscopic.
Natural Background Natural background is the radiation around the instrument caused by natural pro-
cesses. First, there are particles and photons coming from space, including the radiation of sun and
cosmic rays. This type of natural background is called the cosmic background. There are certain
materials in the earth land masses that are radioactive, such as uranium, thorium or potassium.
This material is called naturally occurring radioactive material or NORM).
Naturally Occurring Material (NORM) Naturally occurring materials are, e.g., potassium
40
K, thorium
232
Th and uranium ore, which by now has arrived in its radium ground state and consequently is
reflected by a radium
226
Ra spectrum. NORM constitutes the terrestrial background radiation.
Neutron detector There is an optional detector in RADEAGLET for detecting neutrons. Several neutron
detectors designs exist. The
3
He-tube is the most efficient detector for its size. It is similar in size
to the Geiger-Müller tube, but it utilizes
3
He gas that is in limited supply. Due to this limited supply,
the gas prices have risen and it has become much more expensive in the past few years.
© innoRIID GmbH RADEAGLET User Manual• Software 2.1.16 • Document 1.32o • 2017-12-15 Page 47 of 60