Author/Authors :
Suzuki، نويسنده , , D. and Bazin، نويسنده , , D. and Mittig، نويسنده , , W. and Lynch، نويسنده , , W.G. and Hewko، نويسنده , , C. Le Roux، نويسنده , , A. and Ben Ali، نويسنده , , D. and Browne، نويسنده , , J. and Galyaev، نويسنده , , E. and Ford، نويسنده , , M. and Fritsch، نويسنده , , A. and Gilbert، نويسنده , , J. and Montes، نويسنده , , F. and Shore، نويسنده , , A. and Westfall، نويسنده , , G. and Yurkon، نويسنده , , J.، نويسنده ,
Abstract :
A Micromegas detector was tested in a helium–carbon dioxide mixture at atmospheric pressure. A stable operation of the detector was confirmed at a gain of over 103 for a standard alpha source of 241Am. In order to realize a position-dependent gain, an anode strip was biased while keeping the other strips at the ground potential. The gain of the biased strip was reduced by one order of magnitude without affecting the gains of the neighboring strips. The energy spectra at 3.7 MeV, the energy deposited by Am alpha particles in the sensitive region of the Micromegas, were obtained from the total charge and the charge deposit profile along the track. The energy resolutions for helium:carbon dioxide 90:10 mixture at a gas gain of about 100 were 11% FWHM for the former and 4% FWHM for the latter. The present results highlight the Micromegas as a promising electron amplifier of the forthcoming active target time projection chambers that will be dedicated to nuclear reactions with radioactive isotope beams.
Keywords :
Micromegas , Time projection chamber , Active target , Radioactive isotope beam , Nuclear reaction , Helium
