Self Testing Functionality of the LHC BLM System

Re­li­a­bil­i­ty con­cerns have driv­en the de­sign of the LHC BLM sys­tem through­out its development, from the early con­cep­tu­al stage right through the com­mis­sion­ing phase and up to the lat­est de­vel­op­ment of di­ag­nos­tic tools. To pro­tect the sys­tem against non-conformities, new ways of au­to­mat­ic check­ing have been de­vel­oped and im­ple­ment­ed. These checks are reg­u­lar­ly and sys­tem­at­i­cal­ly ex­e­cut­ed by the LHC op­er­a­tion team to in­sure that the sys­tem sta­tus after each test is "as good as new". This checks the elec­tri­cal part of the de­tec­tors (ion­i­sa­tion cham­ber or sec­ondary emis­sion mon­i­tor), their cable con­nec­tions to the front-end elec­tron­ics, the con­nec­tions to the back-end electronics and their ability to re­quest a beam abort. Dur­ing the instal­la­tion and in the early com­mis­sion­ing phase, these checks proved in­valu­able in find­ing non-con­for­mi­ties caused by un­ex­pect­ed fail­ures. This paper will de­scribe these checks in de­tail, com­ment­ing on the lat­est perfor­mance and the typ­i­cal non-con­for­mi­ties de­tect­ed. A sta­tis­ti­cal anal­y­sis of the LHC BLM sys­tem will also be pre­sent­ed to show the evo­lu­tion of the var­i­ous sys­tem pa­ram­e­ters.