ANORDNING FOR UNDERSOKNING AV BORRHAL I BERG OCH JORD MEDELST UPPREPADE PULSER AV HOGENERGINEUTRONER

摘要

Disclosed is a system for nuclear well logging in which neutron pulse time duration for a high energy neutron generator and the frequency of pulses are selected downhole in the tool by use of a coded signal transmitted by the cable from the earth's surface. Separate channel systems are provided in the downhole tool for desired neutron pulse width and repetition frequency and are operated by a decoder system. Additionally, the accelerator voltage on a high energy neutron generator is controlled by a downhole switching system to selectively obtain different neutron output in response to coded signal transmissions. Moreover, provisions for obtaining different timing pulses to control gates for sampling signals generated in the tool are provided.