The Giga Bit Transceiver based Expandable Front-End (GEFE)* is a multi-purpose FPGA-based radiation tolerant card, produced under the CERN Open Hardware License (CERN OHL). It is foreseen to be the new standard FMC carrier for digital front-end applications in the CERN BE-BI group (equivalent to what the VFC-HD is for the back-end applications). Its intended use ranges from fast data acquisition systems to slow control installed close to the beamlines, in a radioactive environment exposed to Total Ionizing Doses (TID) of up to 750 Gy.

The GEFE takes advantage of the Giga Bit Transceiver (GBT)/Versatile Link developed by the CERN PH-ESE group. This provides a rad-hard, high-speed (4.8 Gbps), bidirectional, optical link (named Versatile Link) for communication with back-end electronics, and multiple low-speed (40 at 80 MHz, 20 at 160 MHz or 10 at 320MHz) electrical links (named e-links) for communication with digital front-end electronics. The communication through the GBT/Versatile Link can be fixed and deterministic in clock phase and data latency if required. In addition to the GBT/Versatile Link, the GEFE features a custom Electrical Serial Link Transceiver (ESLT), to be used in low-speed communications over copper cable through long distances (tested up to 2 km at 10 Mbps).

In order to maximize the versatility, the GEFE is expanded with dedicated mezzanine cards through a High-Pin Count FPGA Mezzanine Card (FMC HPC) connector. This feature gives users the possibility of having an application specific digital or mixed-signal system, for interfacing with front-end electronics. For instance, the GEFE could be expanded with an ADC mezzanine card for sampling the analogue signals from a beam position monitor (BPM), or with a mezzanine card featuring a connector for plugging the GEFE onto the backplane of a crate.

The use of an FPGA, coupled with flexible powering, clocking and FPGA programming schemes, provides the capability to adapt the GEFE for interfacing to the user`s systems. Moreover, the variety of optical and electrical interfaces on the board, in addition to its flexible architecture, mean that it can easily be adapted for use in many different applications where radiation tolerance is a requirement.

Image of GEFE*

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