A 1-GHz Flash-ADC module for the tagging system of the CP-violation experiment NA48

An 8-bit 1-GHz Flash-ADC module has been developed for the tagging system of the CP-violation experiment NA48 at CERN. The module contains two independent channels with 500 MHz sampling rate, which can be interleaved to obtain one channel with an effective sampling rate of 1 GHz. Both FADC chips run continuously and data samples are stored for 524 μs in a ringbuffer memory until they are overwritten by new data. During their “lifetime” data can be extracted from the ringbuffer without disturbing the write cycles. The module fits into a VXI-D crate and uses the VME bus. The design, construction, operation and performance of this module are presented.