4.6
Detector Probe
The T401 Contamination Monitor is equipped with a thin window Geiger Muller detector located in a special
probe attached to the head of the monitor. The detector has the capability to measure alpha, beta and
gamma radiation over a wide range of energies and its delicate, recessed front window is protected by an
open mesh steel grille during use. (Although the mesh provides protection from a rupture of the thin
window by large objects during use, the window remains delicate and vulnerable to puncture by thin
sharp objects and care should be exercised at all times when carrying out monitoring operations).
The detector probe normally rests within a special yoke attached to the monitor, with the face of the probe
orientated into and protected by the main body of the monitor. This orientation is recommended
during storage or transportation. The probe is connected to the monitor via a flexible cable which
is normally retained within the horseshoe -shaped skid attached to the monitor.
The probe is designed to be used in three possible ways during monitoring operations:-
Probe remains attached to the monitor yoke but rotated to suit monitoring requirements.
Probe and the yoke are decoupled from the b ody of the monitor for hand operation. The
flexible cable allows remote operation up to 1.5 -metres from the body of the monitor.
Probe and yoke are removed from the body of the monitor and attached to the
extendable arm (purchased option). The orientation of the probe is adjustable relative to the
extension arm to provide maximum flexibility when monitoring. (Further information on these
monitoring options is provided in section 6 describing the detector probe).
4.7
Calibration
Current UK legislation requires that all operational radiation monitors are subject to annual inspection and
testing. This requirement includes for performance checks and where appropriate, recalibration of
the monitor.
The calibration due date will be displayed on a label attached to t he monitor. This date will indicate
the 12-month anniversary of the current calibration. This can be added to appear on the monitor
screen during start up if requested on purchase or when calibrating the monitor; then when switching
on the contam ination monitor, the next calibration check due date will register automatically on
the screen for approximately 2 seconds.
All Tracerco radiation monitors are checked and calibrated immediately prior to despatch to the
customer. Following this initial procedure (or the annual inspection and calibration check), Tracerco
operatives will re-set the next calibration check due date within the software of the monitor.
For further information on the calibration procedure refer to sectio ns 7.3 and 9.
