PROCESS OF CALIBRATION OF AVIATION GAMMA SPECTROMETER Russian patent published in 1995 - IPC

FIELD: geophysics. SUBSTANCE: calibration is conducted with the aid of source of point gamma radiation. Angle of semi-visibility is divided into a number of conjugate angles and source of point gamma radiation is placed in turn in center of each of them. Speed of counting in photopeak is measured for each position of source. Sensitivity of spectrometer to density of flux of monoenergy gamma quantum is found in these angles. On the basis of obtained data sensitivity of spectrometer to content of radio nuclides in locality for any altitude of detector above its surface is determined under any known distribution of radio nuclides in depth of soil. Obtained value of sensitivity is checked by decrease of value of conjugate angles and by measurement and calculation. If calculated value of sensitivity coincides with preceding one measurements are stopped and calculated value of sensitivity is taken as true one. If detector is placed in anisotropic position relative to its working axis detector is rotated about this axis during process of measurement of speed of counting in photopeak with speed multiple of integer number of revolutions per one measurement. Distance between source and detector is established depending on condition: flat angle at which detector is seen from point of position of source should not exceed value of conjugate angle. EFFECT: enhanced calibration authenticity. 2 cl, 2 dwg, 1 tbl