Electronic (eDAQ)

Our service specializes in the design of data acquisition systems for particle physics detectors. These systems are designed to handle a wide range of readout channels, from a few hundred to several tens of thousands.

Typically, our systems consist of front-end electronics, followed by a signal digitization stage, and finally by the processing of large volumes of data. To achieve this, we use programmable logic devices such as SoCs (Systems on Chip), FPGAs (Field-Programmable Gate Arrays), as well as memory modules. We also implement high-speed links to efficiently handle data rates of several tens of gigabits per second.

Our circuit-board design team has extensive expertise in multilayer PCB design, as well as flexible and rigid-flex circuit-board design. The team also has strong expertise in advanced technologies such as high-density interconnect (HDI) substrates, stacked vias, blind vias, and buried vias.

We design data acquisition systems tailored to the specific needs of physics experiments, taking into account the interface with the detectors being used.

Here are some examples of systems we have developed for different experiments:

CMS Muon

The iRPC chambers are gaseous detectors used in the muon system of the CMS experiment during the CERN HL-LHC phase, over a period of 15 years. When a particle passes through this type of detector, it generates an electron avalanche, producing a signal on copper strips. These strips are then read out by front-end electronic boards.

Each chamber consists of two Bakelite electrodes containing a suitable gas mixture, with two large PCBs located between them and carrying conductive strips embedded in a dielectric layer. The electrodes are operated at a voltage of 7 kV. When a particle passes through the gas, it generates an avalanche of charges, producing a signal on the strips. This signal is collected from both sides and processed by an acquisition board.

On each acquisition board, the analogue stage includes six PETIROC ASICs (Omega), which amplify and detect very small electrical charges, of the order of 50 fC. The received signals are timestamped by three FPGAs hosting multi-channel TDCs, with 34 channels per FPGA and a precision of a few tens of picoseconds. These timestamps are then filtered and grouped into clusters according to timestamps associated with the same strip in order to optimize bandwidth usage. The resulting data are then transmitted to a backend board located outside the detector through a dedicated 4.8 Gb/s optical link. These clusters are used to reconstruct the 3D position of muon hits in the detector.

DUNE

For the DUNE project, we developed a system combining two electronic-board architectures. The first, the AMC board, was developed in-house and is designed to handle 64 analogue channels while transmitting the data over a 10 Gbit/s Ethernet connection.

The second board, known as the “White Rabbit” board, is responsible for distributing clocks throughout the system and generating synchronization frames. In total, we integrated 400 AMC boards into a MicroTCA chassis, corresponding to the digitization of 150,000 analogue channels.

RICOCHET

The RICOCHET project aims to develop dedicated electronics for the readout of bolometers installed inside a cryostat. This electronics system includes a low-noise front end and a digitization stage for the readout channels, and is built around a Cyclone V FPGA with an integrated ARM processor.

The FPGA manages system control, consolidation of the bolometer data, and data extraction through an optical-fibre Ethernet link. The system comprises 30 boards, each equipped with seven readout channels, for a total of 210 channels.

Partnership with the Microelectronics Group

Our expertise in firmware design has led to a close partnership with the Microelectronics Group. Our responsibility is to develop complex digital functions intended for integration into ASICs, whether mixed-signal or fully digital.

This partnership enables us to play an important role in the development of these ASICs, which are essential for many particle-physics applications.

PCB:

• Multilayer printed circuit boards
• Flexible and rigid-flex technologies
• Prototyping, production and production monitoring
• Mechanical integration

Programmable logic devices:

• CPLD
• FPGA
• SoC

Implemented technologies:

• DDR
• PCI Express
• High-speed data links (10 Gbit/s Ethernet)

Timing and synchronization:

• FPGA-embedded TDC
• White Rabbit system