Model 3003 and 3003i Multi-Detector Survey Meter / SCA
Section 2
Ludlum Measurements, Inc.
Page 2-5 September 2020
Example of a Check Source reading:
Check Source #_________ Rate__________ Units________
Once this procedure has been completed, the instrument is ready for use
Sigma Audio
The Ludlum Model 3003 has the standard "click" audio that is widely used
by radiation instruments; 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 seconds on power-up, and then automatically sets a low
threshold alarm rate above the background rate. Then 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.
Detector Failure Diagnostic
Note that the Model 3003 has its own diagnostic tests to ensure that the
detector is functioning correctly. The Model 3003 can detect when the
radiation detector is malfunctioning and will flash the display to indicate a
fault.
Detector Loss Of Count
If the detector stops detecting radiation for a settable number of seconds,
the Model 3003 will flash a zero reading for the currently selected units.
This indication is common if the unit is powered up without a detector
connected. 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.
