Data Readout Method Of Deep Sea In-situ Environmental Nuclear Radiation Detector

The 21st century is the century of the ocean.Ocean area accounts for about 70%of the earth,of which the deep sea area accounts for 49%.The deep sea is rich in mineral resources,water resources and biological resources,which is the treasure house of human beings.Relevant research shows that the deep sea sediments,cold seep and hydrothermal vent activities,active faults,geological tectonic activity,etc.,will cause obvious radiation anomalies.Research on deep sea in-situ nuclear radiation is not only conducive to the assessment of geological activities,biological living environment and the discovery of seabed mineral resources and other important resources,but also to the accurate assessment of marine pollution,which is of great significance for marine environmental protection.In order to enhance the practical ability of deep-sea exploration of China,meet the demand of deep-sea sedimentation,geological structure,radiation monitoring,biological environment and other directions,carry out the research of high-sensitivity deep-sea in-situ environmental nuclear radiation detection equipment is necessary.The in-situ environmental nuclear detectors include crystal gamma detector,CZT gamma detector,scattering neutron spectrometer and instantaneous capture detector.Due to the difficulties of deep-sea exploration,the detector is limited by volume,weight,power consumption,structure and communication bandwidth,the readout scheme of nuclear radiation detection in laboratory cannot be directly used in deep-sea exploration.It is necessary to design special readout scheme for deep-sea nuclear radiation detection.At the same time,to ensure the unity of the interface design and simplify the readout electronics to reuse as much as possible,these four deep-sea nuclear radiation detectors need to use a common readout scheme.To carry out the study of data readout methods in deep-sea in-situ environment nuclear radiation detectors,this paper first investigated the readout methods of the existing deep-sea nuclear radiation detectors and the readout methods of nuclear radiation in other fields.Secondly,this paper designs the readout architecture of the deep-sea nuclear radiation detector based on digital multi-channel pulse height analyzer technology and MODBUS bus communication technology.In order to simplify and reuse the readout circuit of the detector as much as possible,this paper uses the modularization design method to divide the readout electronics into data processing module,general interface module and spectrometer junction module.Among them,the general interface module is the common part of four spectrometers,which is responsible for the control of spectrometers and data storage;the spectrometers junction module is responsible for the back reading of spectrometers'scientific data,which is summarized to the upper computer,the spectrometers junction module also supports the simultaneous back reading ability of multiple spectrometers' equipment data.Aiming at the actual working environment and operation pattern of the deep-sea nuclear radiation detector,this paper designs the behavior and data protocol of the detectors,furthermore,this paper introduces the electronic design of the general interface module and the spectrometer interface module in detail.Then,this paper built the prototype circuit test platform of the spectrometer in laboratory environment and carried on a series of related tests to the general interface module and the spectrometer interface module,including the joint testing of the detector and electronics and host computer software.The test results show that all the electronic modules of the spectrometer work normally.This readout method can support both two operation modes that the real-time collection of energy spectrum under host computer control and the independent collection and storing of energy spectrum without host computer control,which can adapt to the operation mode of the manned submersible and the in-situ experiment station at the same time without modifying the hardware.Besides,this method effectively solves the problem of the compression of energy channels and the case ratio because of the low bandwidth from the underwater communication and the simultaneous readout of multi spectrometer.