Active vibration control method of double crystal monochromator of P2 protein crystallography beam line at SSRF

Abstract

The angular stability of the double-crystal monochromator (DCM) directly affects the positional stability of the focused spot. This paper describes the active vibration control (AVC) method of the DCM of P2 Experimental Station at SSRF based on the adaptive filtering algorithm and the AVC system improves the performance of by optimizing the filter weight estimation algorithm. The simulation results show that the amplitude of the crystal in the pitch direction is greatly reduced by the AVC method, the RMS value of the angular displacement in the pitch direction of the crystal is 1.23 nrad, which is 91.93% lower than the passive vibration control (the RMS value of the angular displacement in the pitch direction is 15.25 nrad); the RMS value of the angular displacement in the pitch direction of the optimized AVC system is 0.233 nrad, which is 98.47% lower than that of the passive vibration control method. The AVC method can effectively ensure the angular stability of the DCM in the pitch direction, which is of great significance for the key equipment of the new generation of synchrotron radiation light source to achieve nano-radian stability.