Thermo Scientific SAM12, Руководство пользователя

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Specification Issue: 1.0
3-2 SAM12 User Manual Thermo Fisher Scientific
Operational Parameters
See Params 1 (page 5-8) , Params 2 (page 5-10) and Params 3
(page 5-11) for information regarding the settings and defaults
for the Operational Parameters.
Software Options
See Options (page 5-6) for information regarding the settings
and defaults for the Software Options.
Vault Options
See Doors (page 5-13) for information regarding the settings
and defaults for the Vault and Door Options.
Default Messages
See Messages (page 5-15) for information regarding the
settings and defaults for the Software Options.
Background Capability
Background capability is related to alarm threshold and
statistical certainty requirements. Background subtraction is
included in the measurement routines for the detectors. When
the isotope of interest is of low energy level, the energy
window can be changed to lower the background count rate
thus allowing greater statistical certainty (see
Hv Power (page
5-28) and Selection of Detector Operating Parameters (page 9-
3) ).
The mean background count rate for use in measurement
calculations is accumulated from a series of 10 second counts,
with a maximum of 10 results stored at any one time. The
mean background count rate is therefore based on a 100 second
count, which is maintained on a “rolling average” basis.
A significant change in the measured background count rate
from the mean will cause the SAM12 to discard the current
mean value and restart background monitoring (see
Changing
Background (page 6-5) ).
If, due to heavy use, the SAM12 has been unable to measure
background for 15 minutes, a 1 second background count is
performed immediately after the current monitoring sequence.
If no significant change is detected, the machine will be
available for further monitoring. If a change in background is
detected, further background measurements are performed until