  A 162.5 MHz superconducting half-wave resonator (HWR) with geometry beta of
0.09 is being developed for Injector II of China Accelerator Driven
Sub-critical System (CADS) Project at the Institute of Modern Physics (IMP).
The HWR section composed of 16 HWR cavities will accelerate the proton beam
from 2.1 MeV to 10 MeV. The RF and mechanical coupled analysis are essential in
geometry design in order to predict the deformation of the cavity walls and the
frequency shift caused by the deformation. In this paper, the detuning caused
by both bath helium pressure and Lorentz force is analysed and a tuning system
has been investigated and designed to compensate the detuning by deforming the
cavity along the beam axis. The simulations performed with ANSYS code show that
the tuning system can adjust and compensate the frequency drift due to external
vibrations and helium pressure fluctuation during operation.
