high energy physics
certificates of quality
N. V. Klopov , E. G. Novodvorsky, S. B. Oleshko, Yu. F. Ryabov
The development of the distributed information systems for quality control (workflow management system) is one from the important directions of the IT services implementation for the automation of the industrial and business processes. A kind of such system was developed to provide information support for the production and assembling of the new detector or particle physics experiment at the Large Hadron Collider (LHC) at CERN. Lessons learned can be useful in developing of such systems in other fields of activity. The main functions of this information system are control of the consistency of the technological operations execution; quantity control on each stage of production; storage of quality control tests data; access to needed data via Internet and online analysis of data dependencies.
The main architecture of data acquisition and data storage systems is represented as two-level distributed database. The first level consists of the set of LDBs under MS Access and the second level is the Central Database (CDB) under one from the relational DBMS (Oracle, MySQL), that contains the full information about technological operations, replicated from LDB, and other data. Query results to CDB data for end-users can be presented in tabular and graphic formats through Web-interface developing on the base of CGI (Common Gateway Interface) scripts.
All users are separated into 3 categories with different rights to data access: executor, manager and system administrator and should be registered in the system beforehand.
As a rule, the description of any technological operations should be started from the manual entry of the operation’s executors and start/finish date. Test results are written into LDB immediately by program or can be stored into external file and load into LDB through GUI afterward. All modified LDB data should be replicated into CDB and “pending replication” mechanism has been implemented. New and modified records are marked by modification flag and during the closure of user session or GUI program they are transferred into CDB. If the connection with CDB server is impossible at that moment, the modification flags still uncleared and data will be replicated later.
To simplify the remote access to CDB data and to give a possibility of creation of conditional request, the Web site for interactive access for the data stored in CDB has been developed. Query result can be presented into different views: simple table, cross-table, histogram and graphics. The e-mail report generator was developed that allows to send to subscribed users reports with the brief description of the fired event (periodical report, increasing the accessible reject rate, consumption of materials).
Additionally, the Passport database (PsDB) under the Oracle DBMS was developed for the preparation and presentation through the Web the quality certificates (passports) for the produced units. Database structure (scheme) and general accompanied software supports the preparation of the different passport types for different units. Due to the different types of the passport data and the probability to change the passport content and structure for any unit type, the data model structure was developed at the high level of abstraction. From this point of view all passport data can be separated to the 3 categories: simple data, tabular data and images (graphical). There are several templates, each of them defines the layout of the presentation and the static content, based on the definite passport type. Template is the HTML file, which includes the special meta-tags. Meta-tag defines the placeholder that will be substituted by the concrete value extracted from PsDB. Templates themselves are stored into PsDB too.
PsDB data can be received from CDB or can be loaded from other sources using the developed web interface.
Proposed approach was realized for integrated assembly control TRT (Transition Radiation Tracker) for detector ATLAS (A Large Toroidal LHC Apparatus). This detector was created in the frame of LHC project at CERN.