Research on Key Technology of Downhole γ Spectrum Logging ²³⁸U Content Based on New CeBr₃ Detector

In order to detect the uranium content of the formation directly through on-site logging technology without uranium radium balance correction and radium radon balance correction in uranium resource exploration, a new type downhole γ spectrum uranium measurement technology based on cerium bromide (CeBr₃) detector was studied. Aiming at the high-intensity γ-ray acquisition requirement of underground uranium ore bodies, a fast digital signal acquisition and processing system based on FPGA was designed, and the γ-ray spectrum data of the standard saturation model well were obtained through actrual measurement. And the effects on the stripping spectrum of 1 001 keV energy peak were compared and analyzed from the 934 keV and 1 120 keV energy peaks of radium series ²¹⁴Bi. And then, the proportional coefficient relationship between ²³⁸U and ²²⁶Ra at the 1 001 keV energy peak was constructed. Finally, the net area of the 1 001 keV energy peak after stripping was used to calculate the ²³⁸U content, which was verified by the national standard saturation model well. The results show that the relative deviation between the ²³⁸U content of each standard saturation model well measured by the 1 001 keV energy peak and the nominal value is within ±10%.