M. Slater

Cavity BPM system tests for the ILC energy spectrometer

The main physics programme of the International Linear Collider (ILC) requires a measurement of the beam energy at the interaction point with an accuracy of 10-4 or better. To achieve this goal a magnetic spectrometer using high resolution beam position monitors (BPMs) has been proposed. This paper reports on the cavity BPM system that was deployed to test this proposal. We demonstrate sub-micron resolution and micron level stability over 20 h for a long BPM triplet. We find micron-level stability over 1 h for 3 BPM stations distributed over a long baseline. The understanding of the behaviour and response of the BPMs gained from this work has allowed full spectrometer tests to be carried out.

Ganga: User-friendly Grid job submission and management tool for LHC and beyond

Ganga has been widely used for several years in ATLAS, LHCb and a handful of other communities. Ganga provides a simple yet powerful interface for submitting and managing jobs to a variety of computing backends. The tool helps users configuring applications and keeping track of their work. With the major release of version 5 in summer 2008, Gangas main user-friendly features have been strengthened. Examples include a new configuration interface, enhanced support for job collections, bulk operations and easier access to subjobs. In addition to the traditional batch and Grid backends such as Condor, LSF, PBS, gLite/EDG a point-to-point job execution via ssh on remote machines is now supported. Ganga is used as an interactive job submission interface for end-users, and also as a job submission component for higher-level tools. For example GangaRobot is used to perform automated, end-to-end testing of distributed data analysis. Ganga comes with an extensive test suite covering more than 350 test cases. The development model involves all active developers in the release management shifts which is an important and novel approach for the distributed software collaborations. Ganga 5 is a mature, stable and widely-used tool with long-term support from the HEP community.

Intelligent Information Access from Scientific Papers

We describe a novel search engine for scientific literature. The system allows for sentence-level search starting from portable document format (PDF) files, and integrates text and image search, thus, for example, facilitating the retrieval of information present in tables and figures using both image and caption content. In addition, the system allows the user to generate in an intuitive manner complex queries for search terms that are related through particular grammatical (and thus implicitly semantic) relations. Grid processing techniques are used to parallelise the analysis of large numbers of scientific papers. We are currently conducting user evaluations, but here we report some preliminary evaluation and comparison with Google Scholar, demonstrating the potential utility of the novel features. Finally, we discuss future work and the potential and complementarity of the system for patent search.

Results from a prototype chicane-based energy spectrometer for a Linear Collider

The International Linear Collider (ILC) and other proposed high energy e{sup +}e{sup -} machines aim to measure with unprecedented precision Standard Model quantities and new, not yet discovered phenomena. One of the main requirements for achieving this goal is a measurement of the incident beam energy with an uncertainty close to 10{sup -4}. This article presents the analysis of data from a prototype energy spectrometer commissioned in 2006-2007 in SLACs End Station A beamline. The prototype was a 4-magnet chicane equipped with beam position monitors measuring small changes of the beam orbit through the chicane at different beam energies. A single bunch energy resolution close to 5 {center_dot} 10{sup -4} was measured, which is satisfactory for most scenarios. We also report on the operational experience with the chicane-based spectrometer and suggest ways of improving its performance.

Recent developments in user-job management with Ganga

The Ganga project was originally developed for use by LHC experiments and has been used extensively throughout Run1 in both LHCb and ATLAS. This document describes some the most recent developments within the Ganga project. There have been improvements in the handling of large scale computational tasks in the form of a new GangaTasks infrastructure. Improvements in file handling through using a new IGangaFile interface makes handling files largely transparent to the end user. In addition to this the performance and usability of Ganga have both been addressed through the development of a new queues system allows for parallel processing of job related tasks.