CERN, Geneva
The role of "Experimental Area Manager" supported by a well organized, charismatic and motivated team is absolutely essential for managing the huge effort needed for a multi-cultural, multi-disciplinary installation of cathedral-size underground caverns housing a billion dollar physics experiment. Between the years 2002 and 2008, we supervised and coordinated the ATLAS work site at LHC, from the end of the civil engineering to the first circulating beams, culminating with 240 workers on the site, 24 hours a day, 7 days a week, with activities taking place simultaneously on the surface, in the 60 m shafts and in the 100 m underground experimental cavern. We depict the activities preparation scheme (including tasks ranging from the installation of 280 ton cranes to super-delicate silicon detectors), the work-site organization method, the safety management that was a top priority throughout the whole project, and the open-communication strategy that required maintaining permanent public visits. The accumulation of experience enables us to summarize the critical success factors for a timely and successful completion of such a vast and complex project.
KEK, Ibaraki
MELCO SC, Tsukuba
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
To maintain the beam orbit of beam transport line from RCS to MR in J-PARC (3-50BT), 14 beam position monitors (BPMs) were installed. Their signals gathered in the local control building (D01) have been measured by using 14 digitizing oscilloscopes. The data acquisition system have a performance of shot-by-shot measurement.
GSI, Darmstadt
Non-destructive profile measurements are preferred not only for single-pulse diagnostics at different locations in a transfer line, but also to enable time resolved observations of stored the beam within a synchrotron. Moreover, the large beam power available at modern hadron accelerators excludes intersecting materials like screens, SEM-grids or scanners. Over the last years advanced concepts were realized: Ionization profile monitors are based on residual gas ionization and their spatially resolved detection. A complimentary method uses single photons detection of beam induced residual gas excitation. A third method is based on the deflection of a crossing electron beam to reconstruct the beam's transverse distribution. At LINACs for negative hydrogen acceleration, a scanning laser beam combined with a photo-electron detector was developed. The transverse profile can be monitored by means of a dedicated pick-up for the determination of the beam's quadrupole moment, i.e. the difference of the horizontal and vertical beam variance. The physical principles and technical realizations of these monitors are discussed.
CERN, Geneva
Mission critical systems at the European Organisation for Nuclear Research (CERN) make extensive use of Programmable Logic Devices (PLDs) such as Field Programmable Gate Arrays (FPGAs) to implement their safety critical functions. The dependability of these safety critical functions is difficult to determine using traditional techniques. A robust approach is needed if PLD technology is to be accepted in mission critical systems. This paper discusses techniques which are being developed and employed by CERN to give confidence in the use of PLDs in mission critical systems, the Safe Machine Parameter system development is used as an example.
CERN, Geneva
We report on first observations and detailed simulations of beam gas rates in the LHC. For the simulations, a comprehensive tool has been set up to simulate in a few hours the expected beam gas losses when pressure maps, collimator settings, and/or beam optics changes. The simulation includes both elastic and inelastic scattering, with subsequent multiturn tracking of proton residues. This provides amongst others a more realistic collimator loss distributions from elastic interactions than what was previously available.
BNL, Upton, Long Island, New York
Future projects for electron-hadron colliders will be reviewed. Existing designs will be presented and, when possible, compared. The challenges and required R&D program will be discussed.
DELTA, Dortmund
A stable beam orbit is essential for safe operation of particle accelerators. This applies to electron machines and even more to hadron machines running high beam currents. Based on developments at DELTA, basic designs of fast orbit feedbacks systems for the FAIR rings SIS18 and HESR (planned) and COSY at the Forschungszentrum Jülich are presented.
CERN, Geneva
Beam-Beam background is one of the main issues of the CLIC MDI at 3 TeV CM. The background level have a significant impact on the interaction region design. This paper presents a study of the background expected rates versus luminosity according to different beam parameters and considering different machine conditions, using an integrated simulation of the Main LINAC and BDS sub-systems.
CERN, Geneva
The operation of the LHC imposes minimum maintenance time, when needed corrections to all systems are to be carried out. Today's maintenance management tools at CERN are seen as too slow and cumbersome for such a challenge. The short duration of the technical stops (72 h/month) requires preparation of jobs in advance, and coordination of all involved teams; at the same time, the radio-protection of personnel in the LHC underground areas imposes a strict "As Low As Reasonably Achievable"(ALARA) policy for the works' duration. In order to perform a maximum of tasks in a short time, a mobile tool for the manipulation of job and equipment data has been created. The ability to signal a new job to a team in the field will avoid unnecessary trips to the tunnel; the signaling of a job's completion (and its details) will allow subsequent jobs to start promptly and with more information; finally, the possibility to consult equipment's full manufacturing and installation data "in situ" will help with the investigation of unforeseen situations. In a 27 km environment with scarce Wi-Fi connectivity, an online light tool is now available, covering the essentials of asset maintenance tasks.
CERN, Geneva
A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. The use of fundamental theorems of the theory of dynamical systems allowed showing that the dynamic aperture has a logarithmic dependence on time. In this paper this result, proven by mean of numerical simulations, is used as a basis for deriving a scaling law for the intensity evolution in a storage ring. The proposed scaling law is also tested against experimental data showing a remarkable agreement.