The GANDALF high-resolution transient recorder system

With present-day detectors in high energy physics one is often faced with fast analog pulses of a few nanoseconds risetime which cover large dynamic ranges. In many experiments both amplitude and time information have to be measured with high accuracy. Additionally, the data rate per readout channel can reach several MHz, which leads to high demands on the separation of pile-up pulses. For such applications we have designed the GANDALF transient recorder with a resolution of 12bit rate at 1GS/s and an analog bandwidth of 500 MHz. Signals are digitized with high precision and processed in real-time by fast algorithms to extract amplitudes and pulse arrival times with a resolution in the picosecond range. With up to 16 analog channels, deep memories and a high data rate interface, this 6U-VME64x/VXS module is not only a dead-time free digitization unit but also has huge numerical capabilities provided by the implementation of a Virtex-5 SXT FPGA. The calculated pulse information can be transferred via the VXS backplane to a central TIGER module which performs trigger decisions spanning a large number of channels.