Readout Process & Noise Elimination Firmware for the Fermilab Beam Loss Monitor System

In the Fermilab beam loss monitor system, inputs from ion chambers are integrated for a short period of time, digitized and processed to create the accelerator abort request signals. The accelerator power supplies employing 3-phase 60 Hz AC cause noise at various harmonics on our inputs which must be eliminated for monitoring purposes. During accelerator ramping, both the sampling frequency and the amplitudes of the noise components change. As such, traditional digital filtering can partially reduce certain noise components but not all. A non-traditional algorithm was developed in our work to eliminate remaining ripples. The sequencing in the FPGA firmware is conducted by a micro-sequencer core we developed: the enclosed loop micro-sequencer (ELMS). The unique feature of the ELMS is that it supports the "FOR" loops with pre-defined iterations at the machine code level, which provides programming convenience and avoids many micro-complexities from the beginning.