Status of the working group activities, June 15th 2020

The following is a summary of the activities that were performed within the working group starting from January 2020.

Concerning the DAQ system:

There has been a comprehensive discussion concerning the overall structure of the DAQ architecture for the EIC detector. In particular:
- A glossary of terms was produced, to make sure that we all agree on the terminology when talking about this subject.
- We invited DAQ experts from different laboratories (JLAB, BNL, CERN) to present the implementations of different DAQ systems.
- We discussed on how to simulate the effect of the trigger in Monte Carlo simulations, in particular for a streaming readout system, as well as how to validate it with data.

A preliminary estimate of the foreseen data rate from the EIC detector was derived by Dr. Jin Huang, for the sPHENIX-EIC detector model Slides
- The main outcome of the study was that, at the nominal detector luminosity, a total readout rate of approximately 100 Gb/s is expected. This includes both the contribution of signal (ep) events and beam-gas interaction (pp) events, together with a first, preliminary estimate of the detector noise. The latter has to be refined.

The output of this discussion was that the whole group thinks that a streaming readout systemis the optimal choice for the EIC detector.
- The main advantages include:modularity, online data treatments, easily adaptable to detection setup changes.
- Critical items to consider:highly demanding on computing and network resources. Also, unexpected large noise level could exceed the system capacity, which must be prepared for such an event.

The following solution was identified:design a modular system evolving with the experiment.
- Hybrid streaming readout during the first (low-luminosity) part of the run to fully understand the detector: if possible, filterless streaming. If unforeseen high-rate from detectors: cross-detector zero suppression, where only interesting portions of the data stream are further processed. This can be achieved both with a parallel hardware system (sPHENIX-like), or with a software system. Calorimeter is an excellent candidate to provide the signature.
- Online filtering and online reconstruction gradually introduced when the detector is under control / online calibrations are available.

Concerning the readout:

We are interacting with the detector WGs to define their requirements in terms of readout: information to read, number of channels, foreseen rates, occupancy, and noise.
- We still need input from few detector groups.
We invited ASICs developers to join our meetings in June, in order to identify if already existing solutions can be used for EIC.
- SAMPA, TIGER, VMM developers already accepted our invitation.

Draft outline of Yellow Report Readout and DAQ section, June 15th 2020

General requirements to the Readout and DAQ system
- Estimate of data rate
- Detector readout requirements with expected hit rates, number of channels
- DAQ requirements
FE and readout
- Existing and future front-end technologies overview
- Application to the EIC detector
- ...
DAQ
- General DAQ structure: streaming readout
- Existing and future streaming readout systems overview
- Application to the EIC detector: the hybrid streaming readout approach
  - Technologies for 100 Gb/s data transport and writing to disk
  - Technologies and solutions for cross-detector zero suppression at the streaming level (possibly reporting both hardware, FELIX-like solutions, and software solutions)
  - Technologies and solutions for online data analysis (possibly reporting a discussion on software frameworks needs and implementations)
- Simulation and validation
- ...
Online data analysis
- Online calibrations
- Online monitoring
- Computing requirements (??)