A survey of the use of database management systems in accelerator projects

The International Accelerator Database Group (IADBG) was set up in 1994 to bring together the people who are working with databases in accelerator laboratories so that they can exchange information and experience. The group now has members from more than 20 institutes from all around the world, representing nearly double this number of projects. This paper is based on the information gathered by the IADBG and describes why commercial DataBase Management Systems (DBMS) are being used in accelerator projects and what they are being used for. Initially introduced to handle equipment builders' data, commercial DBMS are now being used in almost all areas of accelerators from on-line control to personnel data. A variety of commercial systems are being used in conjunction with a diverse selection of application software for data maintenance/manipulation and controls. This paper reviews the database activities known to IADBG

First Experience with Control and Operational Models for Vacuum Equipment in the AD Decelerator

Control and Operational models for Vacuum Equipment have been studied at CERN for several years [1]. A prototype implementation was tried out on ion gauges in LEP followed by a full-scale implementation for all vacuum equipment to be controlled in the newly built AD ring. In order to meet the tight time schedule, the existing hardware and software infrastructure of the PS complex has been used. The model server was built on top of this infrastructure. This has introduced some restrictions with respect to a full implementation of the models, but made the server available for all vacuum equipment already installed in the various accelerators which are connected to this control system. In order to test the server, a simplified man-machine interface has been created. This interface presents the available acquisition and control values in a very homogeneous way to the operator, making the advantage of the chosen model approach evident. It also makes additional diagnostic information, previously unavailable, accessible to the vacuum operators

Control and operational models for vacuum equipment

perational models which describe the behaviour and the physical values associated with the vacuum equipment as seen by an operator have been studied for some time at CERN. Recently, they have been completed by control models, which define in a formal way the data structures required to access the physical values described in the operational model. The control models also define the operations that an application program has to send to the vacuum equipment to modify its state. Object Modelling Techniques (OMT) have been used to formalise the description of the models. In order to test the validity of the concepts, we have made a working prototype in the LEP accelerator. This prototype is being built on top of the CERN SL-Equip equipment access package and uses the "cdev" C++ library, developed at TJNAF, for the interface to application programs. SL-Equip is used for data transmission between front-end computers and vacuum equipment. We use the "cdev" networking facilities to communicate between the workstation and the front-end computers, and the "cdev" generic server as the framework for implementing the vacuum controls software. These packages were used in order to minimise the required software investment, but also to prove that these models are hardware and software independent

The AD Vacuum System: Construction and Commissioning

CERN has built a new experimental facility, called the Antiproton Decelerator (AD), by transforming two existing machines: the "Antiproton Collector" (AC) and the "Antiproton Accumulator" (AA). To achieve adequate beam performance once the antiproton beam is decelerated to its final value of 0.1 GeV/c, it was necessary to lower the average pressure by nearly two orders of magnitude. For this purpose, a large number of additional pumps were installed and a very careful preparation was applied to a variety of special machine equipment which, in its original construction, was not designed for ultra-high vacuum operation. An important improvement in the outgassing rates was achieved through an extended, mild bake-out of tanks and vacuum vessels containing large amounts of ferrite material and multi-layer thermal insulation. This paper describes the necessary modifications of the vacuum system and in more detail the various steps taken to obtain the required pressure in the low 10-10 mbar range. It will also report on the unexpected difficulties which were encountered by re-using vacuum components that were not initially designed for bake-out

Vacuum Stability for Ion Induced Gas Desorption

Ion induced vacuum instability was first observed in the Intersecting Proton Storage Rings (ISR) at CERN and in spite of substantial vacuum improvements, it remained a limitation of the maximum beam current throughout the operation of the machine. Extensive laboratory studies and dedicated machine experiments were made during this period to understand the details of this effect and to identify ways of increasing the limit to higher beam currents. Stimulated by the recent design work for the LHC vacuum system, the interest in this problem has been revived with a new critical review of the parameters which determine the pressure run-away in a given vacuum system with high intensity beams

The LEP Vacuum System: A Summary of 10 Years of Successful Operation

he LEP accelerator is now operating regularly above 100 GeV and its vacuum system is submitted to the impact of energetic photons with a critical energy approaching 1 MeV. The consequences of this high energy on the photon induced desorption will be reviewed in the light of the various photon absorption mechanisms for aluminium. A review will also be given of the ten years of operation of the LEP vacuum system concerning more especially the evolution of the dynamic pressure with the beam dose and energy, the main difficulties experienced and the actions taken to overcome them