Research On γ Measurement System Of Neutron Source Strength Standard With A Manganese Sulphate Bath Method

With the development of nuclear technology, the application of Neutron source is in Nuclear reaction, Nuclear power plant, National defense, Education, Industry, Medicine and Biological Research.Comply with Intensity standard of Neutron source, we can make sure the intensity of Neutron source which be surveyed. We measure accurately the intensity of Neutron source, magnify the measuring range and reduce uncertainty by the Manganese Sulphate Bath Method and referring the Correction coefficient. Besides, we participate in the international contrasts to make measurement working easier. It satisfies institute, oil well logging department and Nuclear power plant for the need of Intensity standard of Neutron source that researching Intensity standard of Neutron source. It gives the standard to instrument of measuring intensity of Neutron source. It also benefits the society and may make some money.The thesis is based on the project AKY0756 of National institute of metrology P.R.China: the research on the intensity of Neutron source mainly through altering Neutron Source Strength Standard based on a Manganese Sulphate Bath Methodthe condition such as adjusting concentration of MnSO4 liquor, changing temperature and speed of liquid and so on.Besides, referring the influence of Correction coefficient of fast Neutron capture, neutron escape and Manganese resonance is also a method to find out the best condition detection efficiency.We need to build Neutron Source Strength Standard with a Manganese Sulphate Bath Method.to fulfill the final purpose based on the project .Neutron Source Strength Standard based on a Manganese Sulphate Bath Method contains two parts: Manganese Sulphate Bath system andγMeasurement System. The stability and detection efficiency ofγMeasurement System influence the stability, detection efficiency and testing data uncertainty of Neutron Source Strength Standard system,so it is necessary to buildγMeasurement System of Neutron Source Strength Standard with a Manganese Sulphate Bath Method.The thesis is about theγMeasurement System of Neutron Source Strength Standard with a Manganese Sulphate Bath Method,and it makes a detail discuss about the measuring principle of neutron source,structure of hardware system,design of software system and adjusting of system.Here is the measuring process: detecting theγ ray of 56Mn emitting by detector instrument of NaI (T1), then enlarging and identifying the signal by utilizing the Operational Amplifier and Single channel pulse height analyzer, last recording the count by NI card. The software compiled with LabVIEW on PC is used to display the signal.Manganese Sulphate Bath Method is used in measuring of neurton source intensity which is a normally,extensively and accurately used method.here is the principle of Manganese Sulphate Bath Method: Manganese Sulphate Bath is a large enough globular or columned container which is full of MnSO4 liquor.Hang the neutron source which is to be measured in the central of Manganese Sulphate Bath, neutron source emit neutrons constantly and these nuetrons get slowing-down action in the water.without considering the absorb of medium on neutron,all neutrons emitted by the neutron source will be slowed-down into hot-neutrons and absorbed by 55Mn and other materials.The amount of neutron won't be balanced until the neutron source stays long enough in the Manganese Sulphate Bath. Absorb hot- neutron then 55Mn turn into 56Mn, 56Mn transit into excited state of 56Fe after disintegrating,then emitγradiation being into ground state of 56Fe.If 55Mn absorbed all the neutrons emitted by the neutron source ,we can confirm the intensiy of the neutron source through measuringγradiation emitted by 56Mn.Hardware of system mainly contains six modules named detector, pre_amplifier, main amplifier, Single channel pulse height analyzer and Data Acquisition System. Data Acquisition System contains Data Acquisition Card and Data Acquisition System Software. We choose six hardware modules according to the capability demand of the system, and here is the model: NaI (Tl) detector (NaI (Tl) Crystal withΦ40×40mm and Photomultiplier tube of GDB44F module), High Voltage Power Supply of Canberra 3102D module, Spectrum Amplifier of Canberra 2022 module,Single channel analyzer of Canberra 2030 and Data Acquisition Card of PCI-6601 module.We design System data acquisition softwarethe with Labview8.2 programming software. The program is made up of four functional modules:user login, parameter setting, data collection, and data saving. User login module can protect the system security effectively, parameter setting module is used to setup the mode of data acquisition, choose and different acquisition methods need the matching measuring parameters. Data acquisition module includes three measuring modules named Single timing measurement, Single untiming measurement and cycle timing measurement.Different measuring methods applied to making user convenient.Data saving module record the collected datas:measuring times,sum-total amount of channel 0,amount rate of channel 0, sum-total amount of channel 1,amount rate of channel 1,and EXCEL software can be used directly to adjust and deal with the collected datas.In order to make operation convenient and human-computer interaction interface friendly.The programe is designed structral and modular.After capability measuring analysis about program,different measuring methods about the input Fixed-frequency signal should be used to make Measurement error less than 0.0075%, and then the measuring system.program should be into execute program(EXE) after program measuring for the convenience of user and preventing program from checked or modified and insurance of its security and stability. What's more, the data collection program carry on the expansion and the tailor according to the actual situation, just the appropriate changes to the software can be used for monitoring different occasions. It improves effectively the usefulness of the program.Finally, on-line test should been done to theγMeasurement System of Neutron Source Strength Standard with a Manganese Sulphate Bath Method.It is normal to measure.Several experiences have been designed to measuring the system,and here are the measuring results of system: Determine the coefficient of linear time for the system R2=0.999999 (two channels); Linear activity: R0 2 =0.99991034(channel 0), R1 2 =0.99778217(channel 1);System repetition:with background measuring ,single relative standard deviation RSD<3.5%,when radiation source exist, RSD<0.3%,5 groups of two channels except for background measured datas of the average RSD<0.2%;system stability: relative deviation 0<±0.33% (channel 0), 1<±0.05% ( channel 1). The outcomes of system measuring indicate that linear, repetition and stability ofγmeasuring system can be applied in Neutron Source Strength Standard based on a Manganese Sulphate Bath Method and it has made a good foundation for the entire neutron source strength Standard's establishment.