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Lewis, J. H.

Paper Title Page
WPPB02 The LHC Central Timing Hardware Implementation 400
  • J. H. Lewis, J. Serrano, P. Alvarez
    CERN, Geneva
  The LHC central timing requirements are very different from those of the injector chain. Not only is machine's safety and reliability critical, but there are other important differences that have forced a new approach. Unlike the injector chain, the LHC processes cannot be usefully broken up into basic time periods and cycles; rather, they are independent, asynchronous, and of arbitrary duration. This paper presents the hardware and low-level software solutions we adopted and the technologies we used to implement them—in particular, the use of reflective memory, reliable use of the global positioning system as a precise time reference, redundancy, transmission-time calibration, safe beam parameter distribution, and the multitasking event generation hardware we developed to control the LHC machine processes.  
RPPB31 Distributed Timing Diagnostic Applications 677
  • I. Kozsar, J. H. Lewis, J. Serrano, P. Kennerley
    CERN, Geneva
  The CERN timing system delivers events to the accelerator complex via a distribution network to receiver modules located around the laboratory. These modules generate pulses for nearby equipment and interrupts for the local host. Despite careful planning, hardware failure and human error can lead to anomalies within the control system. Diagnosing such errors requires a formal description of the logical and topological timing layout. This paper describes the design and implementation of a suite of timing diagnostic software applications that allow users to quickly diagnose and remedy faults within the CERN timing system.  
FOAA03 The CERN LHC Central Timing, a Vertical Slice 711
  • P. Alvarez, J. C. Bau, S. Deghaye, I. Kozsar, J. Serrano, J. H. Lewis
    CERN, Geneva
  The design of the LHC central timing system depends strongly on the requirements for a Collider-type machine. The accelerators in the LHC injector chain cycle in sequences, each accelerator providing beam to the next as the energy increases. This has led to a timing system in which time is divided into cycles of differing characteristics. The LHC timing requirements are completely different, there are no cycles, and machine events are linked to machine processes such as injection, ramping, squeezing, physics, etc. These processes are modelled as event tables that can be played independently; the system must also provide facilities to send asynchronous events for punctual equipment synchronization and a real-time channel to broadcast machine information such as the beam type and its energy. This paper describes the implementation of the LHC timing system and also gives details on the synchronization in the LHC injector chain that manufactures various beams for LHC.  
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