Research On Power Measurement And Collimation System For DNB

Diagnostic Neutral Beam (DNB) equipment can provide Tokamak with neutral beam for diagnostic. The ion temperature of plasma can be analyzed by injecting diagnostic neutral beam to Tokamak. DNB power measurement and collimation system gets the value and distribution of power before injecting particles to Tokamak, so that the DNB system can be easily controlled and adjusted.This article briefly introduces the DNB system in Institute of Plasma Physics, Chinese Academy of Sciences, and demonstrates the design proposal of DNB power measurement and collimation system, including the choice of test system type, hardware composition and the choice of software development platform; several tache are discussed which include the function and principle of the system, the choice of thermocouple and the data acquisition module based on Ethernet, the design and debugging of double switch circuit as well as the trigger circuit, the design of the software, and so on.Two kinds of methods are used in DNB power measurement and collimation system for calculating the power of diagnostic neutral beam that ended on the power measurement target. One is the sampling method and the other is the method that uses the temperature difference between the inlet and outlet of the cooling water way. The value calculated by both the two methods has been contrastively analyzed. The beam line collimation situation that is around the adjustment of the DNB ion source has been contrastively analyzed by using the temperature rise data on the collimation target. Meanwhile, the power of the beam line that ended on the collimation target has been calculated through sampling method and then be contrastively analyzed with the one based on the power measurement target. The dynamic characteristic of the DNB power measurement and collimation system has finally been analyzed in this article.