A Development of a 40-Gb/s Readout Interface STARE for the AGATA Project

The Advanced GAmma Tracking Array (AGATA) multidetector spectrometer will provide precise information for the study of the properties of the exotic nuclear matter (very unbalanced proton (Z) and neutron (N) numbers) along proton- and neutron-drip lines and of super-heavy nuclei. This is done using the latest technology of particle accelerators. The AGATA spectrometer consists of 180 high-purity germanium detectors. Each detector is segmented into 38 segments. The very harsh project requirements are to measure gamma-ray energies with very high resolution (< 1 x 10(-3)) at a high detector counting rate (50 K events/s/crystal). This results in a very high data transfer rate per crystal (5-8 Gb/s). The 38 segments are sampled at 100 MHz with 14 bits of resolution. The samples are continuously transferred to the control and processing (CAP) module, which reduces the data rate from 64 to 5 Gb/s. The CAP module also adds continuous monitoring data, which results in total outgoing data rate of 10 Gb/s. The serial transfer acquisition and readout over Ethernet (STARE) module is designed to fit between the CAP module and the computer farm. It will package the data from the CAP module and transmit it to the server farm using a 10-Gb/s user datagram protocol (UDP) connection with a delivery insurance mechanism implemented to ensure that all data are transferred.

Automated summary

The AGATA multidetector spectrometer utilizes advanced technology for precise study of exotic nuclear matter and super-heavy nuclei. With 180 high-purity germanium detectors segmented into 38 parts, it can measure gamma-ray energies with very high resolution at a high counting rate. Data is transferred to a control and processing module to reduce data rate before being sent to a computer farm for further analysis.