Ludlum Measurements 25009185, Руководство пользователя

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14 CHAPTER 2. GETTING STARTED
cility for recalibration and/or repair. If desired, multiple readings may be taken at different
distances and/or with different sources so that other scales are checked.
Example of a Check Source reading:
Check Source # Rate Units
2.4 Sigma Audio
The Ludlum Model 3001 has the standard "click" audio that is widely used by radiation in-
struments; however, it also has a Sigma Audio mode that can be enabled to change the audio
sound. This mode is useful for scintillation detectors because their high count rate makes
the "click" audio less useful.
In the sigma audio mode, the instrument measures the background radiation for eight sec-
onds on power-up, and then automatically sets a low threshold alarm rate above the back-
ground rate. Afterwards, the instrument will produce a beep any time that the instrument
"sees" more than this threshold value. The user doesn’t need to watch the display to find a
small increase over background; the user may just listen for multiple beeps. Thus, the unit
has an audio alarm that, on power-up, adjusts to just above the current background level
and provides a sensitive audio indication to the user.
Note that this audio alarm can also work in conjunction with the fixed alarm, i.e. the user
can have both a floating audio alarm (resulting in audio beeps) based on the background
level, and a fixed tone audio and a steady ALARM icon when a predetermined fixed alarm
level is exceeded.
2.5 Detector Failure Diagnostics
Note that the Model 3001 has its own diagnostic tests to ensure that the detector is function-
ing correctly.
2.5.1 Detector Loss of Count
If the detector stops detecting radiation for a settable number of seconds, the Model 3001
will flash the minimum display value to indicate which units have been affected by the loss
of count event. This indication is common if the unit is powered up without a detector con-
nected. If this indication is observed with a connected detector, remove the unit from service
and have it evaluated by a qualified repair and calibration technician.
Ludlum Measurements, Inc.