Scientific workflow management in a distributed production environment

The Compact Muon Solenoid (CMS) high energy physics experiment will comprise several large high resolution detectors each of which will be constructed out of over a million precision parts and will be produced and assembled during the next decade by specialised centres distributed world-wide. Each constituent part of each detector must be accurately measured and tested locally prior to its ultimate assembly and integration in the experimental area at CERN. The CRISTAL (Concurrent Repositories and Information System for Tracking Assembly and production Lifecycles) system is a prototype being developed to monitor and control the production and assembly process of 110000 lead tungstate (PbWO₄) mono-crystals, and their associated fast electronics, to be installed in the CMS Electromagnetic Calorimeter (ECAL). The software will be generic in design and hence reusable for other CMS detector groups. The paper discusses the distributed computing problems and design issues posed by this project