• J. Spanggaard, F. Arnold Malandain, P. Carriere, L. Ropelewski, G. Tranquille
  CERN, Geneva

Gas Elec­tron Mul­ti­pli­ers (GEM) find their way to more and more ap­pli­ca­tions in beam in­stru­men­ta­tion. Gas Elec­tron Mul­ti­pli­ca­tion uses a very sim­i­lar phys­i­cal phe­nomenon to that of Multi Wire Pro­por­tion­al Cham­bers (MWPC) but for small pro­file mon­i­tors they are much more cost ef­fi­cient both to pro­duce and to main­tain. This paper pre­sents the new GEM pro­file mon­i­tors in­tend­ed to re­place the MWPCs cur­rent­ly used at CERN's low en­er­gy An­tipro­ton De­cel­er­a­tor (AD). It will be shown how GEMs over­come the doc­u­ment­ed prob­lems of pro­file mea­sure­ments with MWPCs for low en­er­gy beams, where the in­ter­ac­tion of the beam with the de­tec­tor has a large in­flu­ence on the mea­sured pro­file. Re­sults will be pre­sent­ed from pro­file mea­sure­ments per­formed at 5 MeV using four dif­fer­ent GEM pro­to­types, with dis­cus­sion on the pos­si­ble use of GEMs at even lower en­er­gies need­ed at the AD in 2012.