地面核磁共振找水仪放大器设计.pdfVIP

29 8 Vol1 29 No1 8 2008 8 Ch inese Journal of Scientific Instrum ent Aug. 2008 * 王应吉, 林 君, 荣亮亮, 高东旭, 贾晓晨 ( 130026) : , , , ; , ( NMR) , NMR NMR , , , NMR, 100 m : ; ; ; + : P338 . 9 : A : 460. 4040 Amplifier design of surfacenuclearmagnetic resonance instrument for undergroundwater investigation W ang Y ingji, L in Jun, Rong Liangliang, Gao Dongxu, Jia X iaochen (Jilin University, K ey Laboratory of Geo-exp loration and Instrum entation, M inistry of Education, C angc un 130026, C ina) Abstract: A ccor ing to the characteristics that hy rogen nucleus in w ater is paramagnetic an its nuclearmagnetic moment is not zero, a evice is use to transm it a bouquet of Larmor frequency electrom agnetic w aves to the un er- groun , w hich excites the hy rogen nucleus in un ergroun w ater an thus formsmacro hy rogen magneticmoment. A fter removing the excitation signa,l the NMR ( nuclear magnetic resonance) signal generate by macro magnetic moment recovering can be receive . U sing its initial amplitu e, phase, an relaxant tmi e, the correspon ing infor- mation of un ergroun w ater can be calculate . NMR signal is a w eak signalw ith w i e frequency ban w i th. Our NMR amplifier has goo selectivity, strong ab ility to etectw eak signal an can be a juste flexibly, finely an in- telligently. Th is amplifier has been successfully applie to a prototypeNMR un ergroun w ater exploration system, w hich has successfully etecte un ergroun w ater at a epth of 100 m eters. Keywords: NMR ( nuclearmagnetic resonance); un ergroun w ater; amplifier; filter