Sequence Control System of 1 MW, 352.2 Mhz CW Klystron Amplifier

Abstract

A 1 MW, 352.2 MHz, RF test set up based on Thales make TH 2089 klystron amplifier, having both CW and pulsed capability is being developed at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore for characterization and qualification of RF components, cavities and related subsystems. Provision to vary RF power from 50 kW to 1 MW with adequate flexibility for testing wide range of RF components has been incorporated in this test set up. A high power radio frequency (RF) system is always equipped with an interlock and protection circuit for its reliable and safe operation. In an RF system, RF input, all the DC bias power supplies and water cooling parameters like flow and temperature need to be switched ON/OFF in a certain predefined timing sequence to prevent damage to the high power RF device (in this case klystron) and its system. So sequence control system is basically for protecting the klystron amplifier. The sequence control system of 1-MW CW klystron has been developed in order to drive the 1-MW, 352.2 MHz klystron amplifier (TH 2089). The system is able to control the operation of several power supplies and many environment conditions. The hardware of sequence control and the interlock system are based on the NI cRIO 9081(Integrated 1.06GHz Dual Core Controller). Proposed application software is built on LabVIEW 2011 platform and designed to work on Microsoft window environment. The basic function of the software is to check and indicate all the interlocks & log the data before providing power to klystron. The data in this system is acquired with real time visualization. The software will acquire system parameters like status of various mains and power supplies, RF status, various channel status and selection, interlocking system and other incoming status signal as per predefined test sequence. It process acquired data and control the system to achieve user define goals. Additionally, a protection circuit senses the fault conditions such as overvoltage, over-current, high water/air temperature, low water flow, arcing etc. and generates trips which in turn switch off the supplies in a controlled sequence. Communication between PC and real-time controller is established through standard Ethernet. Provision for offline fault analysis based on settable pre and post trigger mechanism has also been incorporated.