• A. Gennai, F. Bedeschi, S. Galeotti, C. Magazzu, F. Paoletti, E. Pedreschi, F. Spinella
  INFN-Pisa, Pisa
• D. Passuello
  University of Pisa and INFN, Pisa

Su­per­con­duc­tive cav­i­ties for fu­ture lin­ear ac­cel­er­a­tors, such as ILC, have ex­treme­ly large qual­i­ty fac­tors re­quir­ing an ef­fec­tive sta­bi­liza­tion with both slow and fast tuners. Piezo­elec­tric ac­tu­a­tors are the most com­mon choice for fast tuners, but one draw­back for a large scale ap­pli­ca­tion is the lim­it­ed band­width and the large cost of com­mer­cial­ly avail­able drivers. In this paper we pre­sent a low cost driv­er which is ide­al­ly suit­ed for fast tuner ap­pli­ca­tion, large sys­tem pack­ag­ing and has an ex­cel­lent flex­i­bil­i­ty in its im­ple­men­ta­tion. Driv­ing piezo­elec­tric ac­tu­a­tors hav­ing ca­pac­i­tive loads up to a few mi­cro­farads in the kHz range re­quires am­pli­fiers with good cur­rent out­put ca­pa­bil­i­ties at a few hun­dred volts. The Piezo Con­trol Unit we de­vel­oped for the ILC Test Area at Fer­mi­lab is com­posed by a 6U Eu­ro­card crate host­ing 5 Piezo Driv­er mod­ules ca­pa­ble of driv­ing up to 10 piezo­elec­tric ac­tu­a­tors. Main spec­i­fi­ca­tions in­clude large volt­age rails (-175 V to +175V), wide sig­nal band­width (DC to10 kHz) and low out­put noise ( <10 mVrms). The driv­er is equipped with both out­put volt­age and out­put cur­rent mon­i­tor.

• F. Spinella, F. Bedeschi, S. Galeotti, A. Gennai, E. Pedreschi
  INFN-Pisa, Pisa
• A. Basti, D. Passuello
  University of Pisa and INFN, Pisa

Ac­tive de­vices based on piezo­elec­tric ac­tu­a­tors are wide­ly used to dump un­want­ed vi­bra­tions in a va­ri­ety of ap­pli­ca­tions; for in­stance fast tuners for su­per­con­duct­ing RF cav­i­ties. In an­oth­er poster, we de­scribe a low cost mod­u­lar sys­tem of drivers for piezo­elec­tric ac­tu­a­tors de­vel­oped at INFN-Pisa; we show here that the same sys­tem can eas­i­ly be ex­tend­ed, with the in­clu­sion of a sim­ple plug-in board, to in­clude suf­fi­cient I/O and com­put­ing ca­pa­bil­i­ty to allow con­trol of the de­vice up to fre­quen­cies in the kHz range. This im­ple­men­ta­tion is ex­treme­ly cost ef­fec­tive and can be used in all sit­u­a­tions where a high gran­u­lar­i­ty dis­tribut­ed con­trol sys­tem is de­sir­able. We also show our first test re­sults ob­tained using this sys­tem to con­trol a warm sin­gle cell 1.3 GHz cav­i­ty. The cav­i­ty is per­turbed using a piezo­elec­tric ac­tu­a­tor to gen­er­ate ran­dom noise, while an­oth­er piezo is used in the con­trol loop to sta­bi­lize the res­o­nance fre­quen­cy. We use the phase of the RF pick­up from the cav­i­ty as a mea­sure of the de­vi­a­tion from the res­o­nance caused by the per­tur­ba­tion. This sim­ple setup al­lows to eas­i­ly test var­i­ous con­trol al­go­rithms with­out the need to work at large com­plex fa­cil­i­ties.