MTCA UPGRADE OF THE READOUT ELECTRONICS FOR THE BUNCH ARRIVAL TIME MONITOR AT FLASH

Bunch Arrival time Monitor (BAM) is an electro-optical device used at FLASH accelerator in DESY for the high precision, femtosecond scale, measurements of the moment when electron bunch arrives at the reference point in the machine. The arrival time is proportional to the average bunch energy, and is used to calculate the amplitude correction for the RF field control. Correction is sent to the LLRF system in less than 10 us, and this creates a secondary feedback loop (over the regular LLRF one), which is focused on beam energy stabilization - beam feedback. This paper presents new MTCA BAM readout electronics design based on the MTCA.4 - “MTCA for Physics”, and FMC mezzanine boards standards. Presented solution is a replacement for existing, VME based BAM readout devices. It provides higher efficiency by using new measurement techniques, better components (such as ADCs, FPGAs etc.), and high bandwidth MTCA backplane. MTCA provides also different topology for data transfers in the crate, which all together opens new opportunities for the improvement of the overall system performance.