ATLAS TDAQ RoI Builder and the Level 2 Supervisor system

The ATLAS High Level Trigger (HLT) uses information from the hardware based Level 1 Trigger system to guide the retrieval of information from the readout system. The Level 1 Trigger elements (jet, electromagnetic, muon candidate, etc.) determine Regions of Interest (RoIs) that seed further trigger decisions. This paper describes the device - the RoI Builder (RoIB) - that collects these data from the Level 1 Trigger and the Level 2 Supervisors (L2SV) Farm that makes these data available to the HLT. The status of the system design and the results of the tests and integration into ATLAS TDAQ system are presented.