Nuclear Techniques ›› 2019, Vol. 42 ›› Issue (12): 120202-120400.doi: 10.11889/j.0253-3219.2019.hjs.42.120202


Influence of slug tuners on the field stabilization tuning of CSNS DTL

Peihua QU1,2,Huachang LIU1,2,Ahong LI1,2,Jun PENG1,2,Qiang CHEN1,2,Xiaolei WU1,2,Bo LI1,2,Mengxu FAN1,2,Yun WANG1,2,Keyun GONG1,2   

  1. 1. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
    2. Spallation Neutron Source Center, Dongguan 523803, China
  • Received:2019-08-26 Revised:2019-10-11 Online:2019-12-10 Published:2019-12-18
  • About author:QU Peihua, female, born in 1991, graduated from Xidian University with a master’s degree in 2014, focusing on proton linac accelerator|QU Peihua, female, born in 1991, graduated from Xidian University with a master’s degree in 2014, focusing on proton linac accelerator
  • Supported by:
    National Natural Science Foundation of China(11105166);Youth Innovation Promotion Association of Chinese Academy of Sciences(201511)

Abstract: Background

The Chinese spallation neutron source (CSNS) drift tube linac (DTL) accelerator has been put into operation since December 2015. During the low power measurement of the DTL cavity, except for DTL-1, the operating frequencies of DTL-2, DTL-3 and DTL-4 were all lower than the design value, and the frequency to be compensated exceeds the tuning range of the slug tuners. It was found that the insertion of the slug tuners was too deep and cavity modes were coupled, which destroyed the double-period chain of the cavity.


This study aims to change the DTL structure to make field stability meet the engineering requirements.


The computer simulation technology microwave studio (CST MS) was used to calculate the stability characteristics of the axial electric field, and the grouping rule of the post couplers (PCs) was given, which accelerated the tuning efficiency. The internal length of DTL-2 slug tuners reached the adjustment limitation, hence two movable tuners were changed from 50 mm to 60 mm to make the working frequency satisfy design requirements. The tuning rings were added to the PCs of DTL-3 and DTL-4 cavity to increase the frequency.


Experimental results show that the field flatness was within ±2%, the stability was tuned to within ±150% / MHz, and the resonant frequency was adjusted to 323.9 MHz±10 kHz at 25 °C.


With structure adjustment for DTL, measurement results meet the engineering requirements.

Key words: Slug tuner, Field stabilization tuning, Resonant frequency, Double-period chain, Post coupler tuning ring

CLC Number: 

  • TL53