WORKFLOW MANAGEMENT IN THE ASSEMBLY OF CMS ECAL

As with all experiments in the LHC era, the Compact Muon Solenoid (CMS ) detectors will be constituted of a very large number of constituent parts. Typically, each major detector may 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 const ituent part of each detector must be accurately measured and tested lo cally prior to its ultimate assembly and integration in the experiment al area at CERN. Much of the information collected during this phase w ill be needed not only to construct the detector, but for its calibrat ion, to facilitate accurate simulation of its performance and to assis t in its lifetime maintenance. The CRISTAL system is a prototype being developed to monitor and control the production and assembly process of the CMS Electromagnetic Calorimeter (ECAL). The software will be ge neric in design and hence reusable for other CMS detector groups. This paper discusses the distributed computing problems and design issues posed by this project. The overall software design architecture is des cribed together with the main technology aspects of linking distribute d object oriented databases via CORBA with WWW/Java-based query proces sing. The paper then concentrates on the design of the workflow manage ment system of CRISTAL. (C) 1998 Elsevier Science B.V.