BEPCII RF POWER SOURCE AND INPUT COUPLER RF group, IHEP

CONTEXT 1.two transmitter’s status(both finished) 2.two interlock systems for cavities(build east and rebuild west) 3. high power aging for waveguide (east and west) 4. power aging for input coupler 5.some problems solved (isolation transformer and ion pump supply) 6.stable RF power for beam commissioning

2004 Sep ~ 2005. April 1. finished installing ,commissioning and SAT (Site Acceptance Test) for 1st transmitter . 2.finished installing and commissioning for 1st circulator .

2005 Nov ~ 2006. April 1.We finished installing ,commissioning and SAT (Site Acceptance Test) for 2nd transmitter . 2.We finished installing and commissioning for 2nd circulator .

The 1st transmitter’s Picture

The 2nd transmitter’s Picture

The Interlock System for east cavity We built a new interlock system with the 2nd transmitter interlock system for the temperature ,pressure, water flow and so on for the east superconducting cavity. We also set up some interlock signals from LLRF and some remote control signals for network.

The east hall Interlock cabinet

The interface module for certain remote control signal

The Interlock System for west cavity We rebuilt the Interlock system for the west superconducting cavity and made the signal cables and wires for the better interlock layout and functions.

The Interlock System for west cavity before now

high power waveguide aging In July, 2006,we did the high power waveguide aging for the waveguide from the 2nd klystron to cavity. In Augest, 2006,we did the high power waveguide aging for the waveguide from the 1st klystron to cavity. The aging power from 0 to 200kW with full reflectin.

waveguide aging 2nd transmitter 1st transmitter

input coupler power aging Input coupler power aging for the 1st and the 2nd superconducting cavity. The aging power from 0 to150kW at normal temperature. Bias voltage for coupler power aging is from -2kV to +2kV,every 0.2kV one point.

input coupler power aging curve

Number of trips with Power (without DC bias voltage)

Bias voltage coupler power aging From -2kV to 2kV Every 0.2kV one point Some gas out point on different bias voltage different Power

Coupler power aging working picture

some problems from transmitter 1.we succeed to solve the isolation transformer failed for the 1st transmitter which caused the cavity high voltage failed . 2.we found some unstable signals from klystron ion pump power supplies which often caused RF trips .We have taken lot of tries and be doing some tests to avoid the IPS trips.

stable RF power for beam commissioning The RF transmitters have operated for almost 6 months until now ,almost continuous stable RF power for superconducting cavity and good interlock system to protect the cavity. It makes good condition for the BEPCII beam commissioning.

stable RF power for beam commissioning In the future ,we will make the RF transmitter more stable for the long time operation. We will make the control interface easier to use and able to be remotely controllable and intelligent.

Thank you!