Chapter 17 



THE USE OF ACCELERATORS OF CHARGED PARTICLES 



IN INVESTIGATING BORE-HOLES BY THE METHODS 



OF RADIOACTIVE LOGGING 



V. M. Zaporozhetz and E. M. Filippov 



Recently an increasing number of announcements of research, involving 

 the use of radioactive logging ^^^' ^*) in bore-hole investigations, have been 

 appearing in the overseas periodicals. With us similar studies are also being 

 conducted. Hence, it is timely to discuss certain problems of utilizing the 

 well accelei'ators and to consider what new techniques and methods can be 

 introduced into the radioactive logging (RL) of bore-holes. 



Of all the varieties of radiation, which can be obtained by using accelera- 

 tors, there is no sense considering any but the strongly penetrative rays, 

 since the instrument to be lowered into a bore-hole must be securely safe- 

 guarded in a strong container; implying that the emergence of proton, 

 deutron, alpha particles radiation, etc., out of the instrument will be in practice 

 impossible. Consequently ^ve will consider the use of the well accelerators 

 as possible sources of neutrons, gamma rays and electrons. 



Before going on to consider the use of individual types of accelerators let 

 us determine their general superiority over natural sources of radiation, 

 which are commonly used in contemporary radioactive logging. 



The most obvious, although not the most important advantage of accele- 

 rators rests in the possibility of obtaining with their aid a much stronger 

 radiation than is possible with natural sources, whose strength for safety 

 considerations has to be limited. An accelei'ator radiates only on being 

 switched on and therefore can be rendered safe when it is brought up to 

 the surface. Moreover, a considerable strength of the source radiation ^vill 

 allow a sharp increase in the speed of the radioactive investigations of bore- 

 holes. In order to avoid inaccuracies in a case where natural sources are 

 being used this speed has to be very small. This advantage can in principal 

 be very important, and has a significant bearing on production; thus, justi- 

 fying the use of bore-hole accelerators. No less important an advantage is 

 the possibility of obtaining considerable energy from the radiation acceler- 

 ators, whereas in the case of the natural sources such energy is always limited 



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