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Air borne gamma-ray spectrometer, portable/ground gamma-ray spectrometers and jeep/car borne gamma-ray spectrometers

Five concrete calibration pads (K, U(I), U(II), Th and Mix pads) were constructed at civil airport, Nagpur in 1984. The distinctive features of the pads are large size (12.2m diameter), homogeneity in radio elemental concentration, negligible leachability with the rain water, low radon emanation and high density.  These pads are used for calibration of air borne and ground gamma-ray survey equipment. The radio-elemental concentration of each pad is given below:

Pad K (%) U (ppm) Th (ppm)
K 5.28 0.9 2.2
U(I) 0.87 10.4 3.4
U(II) 0.78 21.70 3.2
Th 0.85 1.7 41.8
Mixed 3.85 14.8 21.4

Five transportable calibration pads ( K, U, Th, Mix and BG pads) were also constructed in 2014 which have same features as fixed calibration pads. These pads can be transported to the airbase where airborne surveys are in progress and can also be used for the calibration of portable gamma-ray spectrometers. The radio-elemental concentration of each pad is given below:

Pad K (%) U (ppm) Th (ppm)
K 9.15 0.5 1.8
U 0.3 49 2.9
Th 0.2 5.4 105
Mixed 4.88 23.4 52.3
BG 0.2 0.5 1.8

       

  Calibration facilities for Borehole and shielded probe gamma-ray logging system:

Facilities of calibration of gamma-ray logging systems are available at RSA, HQ, Hyderabad.