Development of digital down conversion based digital beam position monitor for Indus-1

Indus-1 is a 450 MeV synchrotron radiation source (SRS) at RRCAT Indore. For beam position measurement, four button type beam position indicators (BPls) are installed in Indus-I. A digital down conversion (DDC) algorithm based digital beam position monitor (DBPM) has been developed. Xilinx make board having Virtex-t FPGA has been used for implementation of DBPM system. The RF frequency of Indus-1 is 31.613 MHz. This DBPM processes 31.613 MHz pickup signals of beam position indicator by sampling it with 14 bit ADC at 28 MHz clock. The DDC also works at same clock of 28 MHz and generates position output. The output data rate of 10 kSPS and bandwidth of ∼ 2 kHz has been achieved by this system. System has been tested successfully in lab on calibration bench with simulated beam signals. System has also been tested in field. The design details and implementation aspects are discussed in this paper. (author)