The readout of a GEM or Micromegas-equipped TPC by means of the Medipix2 CMOS sensor as direct anode

• DOI: 10.1016/j.nima.2004.07.180
• Publication Date: 2004-08-18T09:05:21Z
• Authors: P. Colas; A.P. Colijn; A. Fornaini; Y. Giomataris; H. van der Graaf; E.H.M. Heijne; X. Llopart; J. Schmitz; J. Timmermans; J.L. Visschers
• Keywords: MicroMegas detector

We have applied the Medipix2 pixel CMOS chip as direct anode readout for a TPC. For the gas ampli?cation two options have been investigated: (i) a three-stage GEM system and (ii) a Micromegas mesh. The structure of the cloud of primary electrons, left after interactions of 55 Fe quanta with the gas is visible with unprecedented precision. This proof-of-principle is an essential step in our project to realize a monolithic pixel sensor with integrated Micromegas, to be developed specially for the readout of TPCs, and applicable for drift chambers in general.