Geophysical Journal | 1999 volume 21 Ή5

Readings of devices with 3He detectors of neutrons in investigating natural media

© Zvolsky S.T., Kulik V.V., Mesropian V.S., Chernigovsky E.A., Molchanovsky S.N., Maistrenko I.A.

Experimental investigations of readings a number of neutron tools with 3He detectors are carried out. Dependencies of the count rate of slow, epithermal and thermal neutrons on the content of anomalous absorbers (boron and chlorine) in water solutions of boron acid and sodium chloride, and also in quartz sand saturated with these solutions are obtained. The physical modeling was conformed to both quasi-homogeneous media, and the borehole conditions. Introduced are quantities not used in nuclear geophysics before, namely cadmium difference and a modified cadmium ratio. An analysis of their properties and potentialities under determination of neutron parameters of absorption is carried out. In particular, it is experimentally established that the linear depen-dence of the modified cadmium ratio on the content of the anomalous absorbers exists not only in the case of a homogeneous medium, but also in the presence of a borehole. On the basis of the performed theoretical and experimental investigations a new modification of the stationary neutron methods of the study of geological media a method of dual-channel integral neutron spectrometry (DINS method) is proposed.

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