Development and Performance Verification of the GANDALF High-Resolution Transient Recorder System

TL;DR

The paper presents the design and verification of the GANDALF high-resolution transient recorder system, capable of high-speed, high-precision digitization and real-time processing for high energy physics experiments.

Contribution

It introduces a novel 12-bit, 1GS/s digitizer module with advanced FPGA algorithms for real-time pulse analysis and pile-up separation in high energy physics detectors.

Findings

Achieved better than 50 ps timing resolution.

Demonstrated dead-time free digitization with high data throughput.

Implemented real-time pulse shape analysis algorithms.

Abstract

With present-day detectors in high energy physics one often faces fast analog pulses of a few nanoseconds length which cover large dynamic ranges. In many experiments both amplitude and timing 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 an upgrade of the COMPASS experiment at CERN we have designed the GANDALF transient recorder with a resolution of 12bit@1GS/s and an analog bandwidth of 500\:MHz. Signals are digitized with high precision and processed by fast algorithms to extract pulse arrival times and amplitudes in real-time and to generate trigger signals for the experiment. 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 Virtex5-SXT FPGA. Fast algorithms implemented in the FPGA may be used to disentangle possible pile-up pulses and determine timing information from sampled pulse shapes with a time resolution better than 50 ps.