A process for the much channel transmission of a radiation spectrum, in particular for the electronic remote sensing of the earth formation within a borehole

摘要

1,160,747. Radioactive borehole logging. BRITISH PETROLEUM CO. Ltd. Dec. 15, 1966 [Dec. 16, 1965], No.53452/65. Heading G1A. A borehole logger comprises a sonde containing a gamma-ray detector, a multi-channel pulse height analyzer and means for transmitting the channel contents to the surface by time division multi-plexed position modulated pulses, and means at the surface monitoring the contents of selected combinations of the channels to provide a display of the energy spectrum of the gamma-rays detected. Pulses produced in a scintillation detector D due to gamma-rays from natural or induced radioactive isotopes in the formations surrounding the borehole are separated by a pulse light analyzer PD into 23 channels. The pulses are standardized by mono-stable circuits M1-M23 and integrated by integrators I1-I23 to produce signals representative of the number of pulses received in each channel. The outputs of integrators I1-I23 are fed in turn through sequentially operated AND gates A1-A23 to a multi-plex transmitter TT. In TT the analogue signals from the integrators are converted into pulse position modulated signals by an integrator and threshold device and transmitted up the logging cable to a multi-plex receiver TR which distributes the position modulated pulses through 23 AND gates B1-B23, to stores ST1-ST23. The contents of the stores may be displayed on a C.R.T. in the form of the spectral distribution of gamma-rays received by the detector, and the contents of selected combinations of stores may be displayed on indicators IND1-IND5 by suitable closure of switches SS1-SS115. The signals from the units TT and TR for opening the gates A1-A23 and B1-B23 are provided by a twelve cathode discharge tube, each cathode of which is connected to two gates selectively operable by a bi-stable circuit controlled from the final cathode of the tube, Fig.2 (not shown).