NUCLEONIX SYSTEMS RC 705E Instruction Manual page 20

For measuring natural background levels, take the unit to the area where actual sample measurements are
to be done. Make sure there are no samples close by. (at least a few meters away). Hold at least 1 meter above
the ground level and 1 metre away from side walls observe the natural background (BG) reading. Make
about three measurements & take average of the three readings & that should be treated as the natural B.G.
(Base value)
We recommend that measurement is done in nSv/hr which is internationally accepted unit. Other units
available in the instrument are R/hr, CPS or CPM.
Samples are available in different stages of processing like raw material entry stage, intermediate processing
5.4.2 MEASUREMENT ON A SAMPLE
state, finished product stage, etc. To detect contamination without missing, maximum number of
measurements that are practically possible, are to be made at various stages of production. The input stage
must be giventhe utmostattention sothat you do not wastetime, money and effort in processing contaminated
raw material.
Samples can be in various shapes and sizes.
To get authentic measurements, Samples must be chosen such that they are:
Sample weight : Total weight is not less than 2 kg
Sample size : Area of sample must exceed front face of the detector probe in case of external probe and front
face of the unit in case of internal detector probe.
If samples/components are small in size, they must be bunched together to meet weight & size criteria as
said above.
To measure for RaC on the sample, press 'START' button to enter into D.RATE mode assuring that D.RATE
mode is default setting, and bring the detector probe close to sample until it touches and covers the probe
face completely.
Once a measurement is completed at the end of TC (=4sec typical) user can 'STORE' the reading if required
& start again for another measurement.
5.4.3 IDENTIFYING WHETHER SAMPLEIS CLEAN / SUSPECTED CONTAMINATION / SURE CONTAMINATION
Make sure that sample size & shape criteria are met as given above.
CASE
When you touch the sample with the meter, if the reading goes lower than BG by more than 10%, then the
Case 'a' – Clean sample
sample is clean.
When you touch the sample with the meter, if the reading slightly falls below BG, but not more than 8%,
Case 'b' – Suspected contamination
then it is a case of suspected contamination. This sample must be examined more carefully by repeating the
measurements with larger masses. Sample can be sent to Nucleonix for ascertaining the contamination.
When you touch the sample with the meter, if the reading remains same or increases, then it is a case of
Case 'c' – Sure contamination
sure contamination.
In case of suspected contamination, samples can be sent to Nucleonix for further analysis by "Gamma Ray
5.4.4 APPROPRIATE ACTION
Spectroscopy System for Radioactive Contamination Measurement by Nuclide Identification & its
quantification". A report will be given in Bq/gm. Nucleonix Systems is offering sample analysis services.
Please refer to our website & click on Radioactive contamination Inspection Systems / Products for Steel
Industry" on home page (last para) & then to choose 'Sample analysis services".
Contact on mobile 9346645906 (Customer Support Division) for further details on this.
If you find that your sample is contaminated, then contact AERB for further help & guidelines on how to
dispose it.
Shri. S.P Agarwal (Head),
Radiological Safety Division,
Atomic Energy Regulatory Board,
Niyamak Bhavan, Anushaktinagar,
Mumbai – 400 094.
Ph : 022‐25574287 Fax : 022‐25565717, 25562344, 25583230 Mobile : 9820864880
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