Ametek ORTEC radEAGLET, Руководство пользователя

Страница: 128 / 140

C.6 Live, Real and Dead Times radEAGLET User Manual
at the detector surface, the radEAGLET switches off the scintillation subsystem and uses
the fall-back GM tube (included in all radEAGLET variants) for dose rate measurements.
A nuclide identification is possible in radiation fields up to 200 µSv/h. Though, a valid and pre-
cise ID is only given if the limits of the EASY-MODE ID are adhered to. Here, the instrument
will clearly indicate, whether an over-range situation exists or not.
C.6 Live, Real and Dead Times
The Multi-Channel Analyzer (MCA) component of radEAGLET is an advanced electronics
component that deploys sophisticated signal processing algorithms for signal interpretation.
The MCA and electronics have a short dead-time after each pulse where no signal will be
seen. This is because the electronics cannot accept a new pulse to be processed while it is
already processing a pulse. The higher the incident count rate, the higher the dead time. The
dead-time accumulates with the measurement time and is dependent on the detector load
in terms of counts per second (cps). Consequently, two acquisition times may be displayed:
the real-time, which is the true time duration of the acquisition and the live-time, which is
the acquisition time corrected by the above defined dead-time. The live time will always be
shorter than or equalt to the real time.
C.7 Scaling of the Vertical Spectrum Axis
Scintillation detectors have a certain energy-dependent sensitivity. Peaks at low energies
(e.g. 59 keV of
241
Am) have a higher sensitivity than peaks at the higher end of the spectrum
(e.g. 1332 keV of
60
Co). When observing this type of spectra and the y-axis has a linear
scale, some peaks at higher energies might not be visible. To see a better display of the
higher energy peaks, you might want to look at the spectrum either using a logarithmic scale
or a square root scale for the y-axis. These different scales allow the user to visually equalize
the peak heights so that a wide range of the spectra can be viewed without zooming.
128/140 Software 3.2.0 • Document 3.2.2o © innoRIID GmbH • 2018-10-24