Nuclear Techniques ›› 2018, Vol. 41 ›› Issue (3): 30101-030101.doi: 10.11889/j.0253-3219.2018.hjs.41.030101


Optimized rotation mechanism of the toroidal mirror at grating monochromator system

CHEN Jiahua1,2, XU Zhongmin1, ZHEN Xiangjun1, XUE Song1   

  1. 1. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading Campus, Shanghai 201800, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2017-11-20 Revised:2017-12-11 Online:2018-03-10 Published:2018-03-14
  • Supported by:
    Supported by National Natural Science Foundation of China (No.11175243)

Abstract: [Background] Rotation mechanism of the toroidal mirror is a main part of the grating monochromator system, which is a key equipment of the soft X-ray spectromicroscopy beamline. Flux stabilization is essential to every experiment. However, a long stabilization time exceeding 2 h causes a serious waste of beamline time. [Purpose] This study aims to reduce the flux stabilization time of grating monochromator system by optimized design of rotation mechanism of the toroidal mirror. [Methods] By analyzing the temperature increase of the toroidal mirror (TM), the total linear thermal expansion along the bar direction is calculated to be 0.97 μm after 2 h, which causes a 141 μm horizontal deviation of the focusing spot from the exit slit center while the horizontal size of the slit is only 50 μm. Hence the rotation of the sin-bar mechanism is caused by the absorption heat load of TM with continuous change of incidence angle, which is the main reason of the flux drift. This problem could be solved by adding an indirect water cooling system on both sides of the TM. [Results] The flux stabilization time has been reduced to about 30 min from more than 2 h after adding the cooling system. [Conclusion] The experiment result shows that the optimized design for reducing the flux stabilization time is feasible and effective, and the efficiency of the beamline could be improved greatly.

Key words: Grating monochromator system, Toroidal mirror, Flux drift, Linear thermal expansion, Indirect water cooling

CLC Number: 

  • TL99