The software of the ATLAS beam pick-up based LHC monitoring system

TL;DR

This paper describes the software system used for monitoring LHC beam timing and properties via ATLAS BPTX detectors, including algorithms, displays, and initial operational results from 2008.

Contribution

It introduces the specific monitoring software and algorithms for the ATLAS BPTX system, detailing its implementation and initial performance during early LHC operation.

Findings

High-accuracy phase measurement between collisions and clock

Monitoring of beam bunch properties and structure

Successful initial deployment during 2008 single beam run

Abstract

The ATLAS BPTX stations are comprised of electrostatic button pick-up detectors, located 175 m away along the beam pipe on both sides of ATLAS. The pick-ups are installed as a part of the LHC beam instrumentation and used by ATLAS for timing purposes. The signals from the ATLAS BPTX detectors are used both in the trigger system and for a stand-alone monitoring system for the LHC beams and timing signals. The monitoring software measures the phase between collisions and clock with high accuracy in order to guarantee a stable phase relationship for optimal signal sampling in the sub-detector front-end electronics. It also measures the properties of the individual bunches and the structure of the beams. In this paper, the BPTX monitoring software is described, its algorithms explained and a few example monitoring displays shown. In addition, results from the monitoring system during the first period of single beam running in September 2008 are presented.