Feedback Configuration Tools for LHC Low Level RF System

The LHC Low Level RF Sys­tem (LLRF) is a com­plex mul­ti-VME crate sys­tem which is used to reg­u­late the su­per­con­duc­tive cav­i­ty gap volt­age as well as to lower the impedance as seen by the beam through low la­ten­cy feed­back. This sys­tem con­tains mul­ti­ple loops with sev­er­al pa­ram­e­ters which must be set be­fore the loops can be closed. In this paper, we pre­sent a suite of mat­lab based tools de­vel­oped to per­form the pre­lim­i­nary align­ment of the RF sta­tions and the be­gin­nings of the closed loop model based align­ment rou­tines. We briefly in­tro­duce the RF sys­tem and in par­tic­u­lar the base band (time do­main noised based) net­work an­a­lyz­er sys­tem built into the LHC LLRF. The main focus of this paper is the method­ol­o­gy of the al­go­rithms used in the rou­tines with­in the con­text of the over­all sys­tem. Mea­sured re­sults are pre­sent­ed which val­i­date the tech­nique. Be­cause the RF sys­tems are lo­cat­ed un­der­ground in a lo­ca­tion which is rel­a­tive­ly un-ac­ces­si­ble even with­out beam and com­plete­ly un-ac­ces­si­ble when beam is pre­sent, these tools will allow CERN LLRF ex­perts to main­tain and tune their LLRF sys­tems from a re­mote lo­ca­tion sim­i­lar to what was done very suc­cess­ful­ly in PEP-II at SLAC.