DESCRIPTION: Each set consists
of four calibrators; 1 each for ranges 0-1000 R/hr, 0-104 R/hr, 0-105 R/hr and 0-106 R/hr. Each calibrator consists of a precision hi-meg resistor housed in a 1-3/8'' x 2-1/4'' x 1-1/8'' cast aluminum case with a connector identical to the probe connector on the CP-MU. Each is hand calibrated and the value stated as a scale reading is engraved on the case.
USE: To calibrate the CP-MU by
the substitution method, a MU calibrator is plugged into the instrument
in place of the probe and the instrument turned to the appropriate range. The reading which appears on the meter should be within ± 10% of the calibration number engraved on the MU case. If it is not within ± 10% the cover should be removed from the appropriate adjustment pot on the front of the case and the pot adjusted by means of a screwdriver until the reading is correct. The range be noted that the MU, by substituting for the chamber, checks and allows calibration of the entire instrument except for the cable and chamber. A radiation source check at a single point will then assure complete operability (see calibration directions in CP-MU Manual of Operation).
SLEEVING OF DMU UNDERWATER PROBES
Model # MU-PT-1 and MU-PT-1000
Polyethylene sleeves are available for each DMU Underwater Probe. A set (Model MU-PT-1) suitable for Probe DMU-1 contains a 60 foot sleeve of 3'' width and a 60 foot sleeve of 5'' width. For the DMU-1000 widths are 10'' and 12'' (Model MU-PT-1000).
While the detector and cable assembly (except for
the connector that fastens to the chrome electronic section) is water-proof
and has been tested to water pressures of 130 feet, it is recommended
that the two sleeves be slipped over the detector and cable and that
the top of the sleeves be kept substantially above waterline. This
prevents any possible leakage of water into the probe due to possibly
a braided or otherwise damaged cable. It also diminishes chances of
contamination the detector or cable.
It should be noted that a weight may be required
in the bottom of the polyethylene sleeve so that the detector will
not float and that as the detector sinks the sleeve should collapse
so that a large air path does not form and allow radiation streaming.
TA TECHNICAL ASSOCIATES
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TELEPHONE (818) 883-7043 * FAX(818) 883-6103
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