Construction status of the CPHS RFQ at Tsinghua University

We present, in this paper, the construction status of a Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The 3-meter-long RFQ will deliver 3 MeV protons to the downstream Drift Tube Linac (DTL) with the peak current of 50 mA, pulse length of 0.5 ms and beam duty factor of 2.5%. The RFQ has been mechanically separated into three sections. A ball-end mill, instead of a forming cutter, is adopted to machine the vane tip due to its varying radius of curvature. The precision of the numerically controlled milling machine has been verified by machining test pieces of aluminum and copper. Fine machining of the vanes was completed in July, 2011. The pre-braze tuning was completed at the beginning of this August. Copyright © 2011 by IPAC'11/EPS-AG.