Speaker
Description
The KEDR experiment is ongoing at the VEPP-4M $e^{+}e^{-}$ collider at Budker INP in Novosibirsk. The collider center of mass energy range covers a wide spectrum from 2 to 11 GeV. Most of the up-to-date statistics were taken at the lower end of the energy range around the charmonia region. Activities at greater energies up to the bottomonia lead to a significant increase of event recording rates and accelerator backgrounds, thus stressing the existing DAQ and trigger systems beyond their limits, so its upgrade was required.
The data acquisition system hardware consists of three types of devices: digitizers, readout processors (RP) which transfer data from digitizers to DAQ computing cluster and sinchronization and control modules (SCM), which accept signals from trigger, enumerate events and distribute commands and reference frequency to readout processors (and from them to digitizers).
The DAQ computing cluster is composed of several similar computers, running the same specially developed software, interacting with each other. It receives data from readout processors via DAQ network, process them according to hardware configuration and builds the events from the fragments transmitted by each RP.
The data acquisition system software covers a full set of management and control tasks, such as hardware management and diagnostics, network diagnostics, management of the software services and the data acquisition itself. It logically binds all hardware components together. The software takes care of the hardware configuration, monitoring and fail-over. It consists of event building services, coordination services and middleware components for interaction. For example, coordination service determines number of required event building services, its configuration, placement and related hardware based on hardware description, requested working mode and available computing resources. Then at data recording time coordination service monitors and maintains the availability of the required services, starts and stops them on request.
The system is scalable horizontally by design, provides high level of parallelization of data transfers and events processing, have improved reliability based on readout computing cluster with redundancy.
Wide range of hardware features and software flexibility gives opportunity to use this data acquisition system for other experiments. For example, the described DAQ system is considered as a prototype of the projected BINP (Super) Charm-Tau Factory or other future BINP HEP experiments like VEPP6.