Design Of Rapid Test System For Electronic Performance In Nuclear Environment

ITER（International Thermonuclear Experimental Reactor）is the second largest scientific project in the world after the International Space Station.Its purpose is to generate a large amount of energy through controlled magnetic confinement fusion to replace traditional fossil fuels and solve the energy crisis.A large number of X-rays are generated during the operation of the ITER,so the Radial X-ray Camera（RXC）is installed in the device to detect the intensity distribution of soft X-ray radiation generated during the operation of the nuclear fusion experimental reactor.The RXC system is installed in NO.12 port of the ITER.RXC consists of detectors,pre-amplifiers,mid-amplifiers and data acquisition system.Because the output signal of the detector is very weak,the pre-amplifier and mid-amplifier need to be closer to the detector.However,the level of nuclear radiation is very high and the space is very narrow near the detector,it leads that the electronic equipment hardly survive.After multi-party research and judgment with experts in ITER,the final placement of pre-amplifiers and mid-amplifiers are in the relatively small radiation area of Port 12cell.Nevertheless,the neutron flux in this room is also as high as 10⁷n·cm^-2·s^-1,and the static magnetic field intensity can reach to 150 m T when the plasma is operated with deuterium and tritium discharge.Radiation damage is prone to occur in the environment where the electronic equipment works with strong nuclear radiation.Therefore,during the maintenance operation of the pre-amplifier and the mid-amplifier,due to the influence of neutron activation,the worker need to wear anti-radiation coats and cannot stay in the radiation area for a long time（the troubleshooting and maintenance work should be controlled within 30 min）.At the same time,in order to optimize the maintenance process,it is necessary to develop a set of special test tools that can quickly and accurately find whether the amplifier performance is reduced or whether the card is damaged.The test tool is special and planned to be delivered to ITER for application.It is designed,manufactured and checked according to ITER requirements for electronic equipment.In view of the above project requirements,this paper introduce an electronic performance automatic test platform on the basis of optimizing the maintenance process.The platform is composed of PXIe portable chassis,multi-channel high-precision signal generator based on PXIe bus,multi-channel data acquisition card（NI PXIe-6368）,SCSI 68-Lemo32 multi-core twisted pair shielding cable and PC software.The PXIe portable chassis is a national high-performance equipment developed by our research group and partners.The multi-channel high-precision signal generator based on PXIe bus is the key research content of this paper.It is designed by Sub card structure,and the mother card uses K7 series FPGA produced by XILINX company as the core processor,which is connected to the child card through the interface.A 16-channel digital-to-analog converter（DAC）and signal conditioning circuit are arranged on the sub-card.The hardware code is programmed by VIVADO,so that FPGA controls 16-channel DAC for digital-to-analog conversion and achieves signal output.The PC code is written by Lab VIEW software,including graphical user interface design and software code design.The graphical interface includes one main interface and two sub-interfaces,which are respectively configuration interface and report generation interface.The main interface is used to display various test results,and the sub-interface is respectively used to configure card parameters and report types.The software code part includes PXIe communication,software algorithm and report generation.PXIe communication part is used for building instruction interaction with the lower computer to control the amplitude and frequency of the output signal of the multi-channel signal generator,so as to achieve frequency and amplitude sweep functions.The software algorithm realizes the test of the amplifiers baseline offset,noise,linearity,gain,bandwidth and other performance.The report generation function realizes the on-site evaluation of amplifier performance,thus simplifying the maintenance process.In this paper,the performance of the electronic performance automatic test platform for RXC is tested and analyzed.The arbitrary waveform generator（Tektronix AFG3022C）is used for standard signal source,and the software algorithm is tested and the interference caused by cable noise is corrected.The output range of multi-channel high precision signal generator based on PXIe bus is tested by standard oscilloscope（TBS 1202B-EDU）,and the bandwidth of the signal generator is measured by NI PXIe-6368 acquisition card combined with software bandwidth algorithm.Finally,the electronic performance of the amplifier is tested by using the electronic performance automatic test platform of RXC,and the test report of the amplifier is generated,so as to realize the performance test of the whole system.The test results show that the signal output range of the multi-channel high-precision signal generator based on PXIe bus is from-10V to+10V,and the-3 d B bandwidth is about 65 k Hz.The software algorithm realizes the expected function.The electronic performance automatic test platform can complete the performance test of a16-channel output amplifier in 10 minutes including the operation of worker,and the test report is generated.The design of the system provides a reference scheme for rapid test of electronic parameters in nuclear environment.