Charge identification of fragments with the emulsion spectrometer of the FOOT experiment

Abstract The FOOT (FragmentatiOn Of Target) experiment is an international project designed to carry out the fragmentation cross-sectional measurements relevant for charged particle therapy (CPT), a technique based on the use of charged particle beams for the treatment of deep-seated tumors. The FOOT detector consists of an electronic setup for the identification of <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mi>Z</m:mi> <m:mo>≥</m:mo> <m:mn>3</m:mn> </m:math> Z\ge 3 fragments and an emulsion spectrometer for <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mi>Z</m:mi> <m:mo>≤</m:mo> <m:mn>3</m:mn> </m:math> Z\le 3 fragments. The first data taking was performed in 2019 at the GSI facility (Darmstadt, Germany). In this study, the charge identification of fragments induced by exposing an emulsion detector, embedding a <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:msub> <m:mrow> <m:mi mathvariant="normal">C</m:mi> </m:mrow> <m:mrow> <m:mn>2</m:mn> </m:mrow> </m:msub> <m:msub> <m:mrow> <m:mi mathvariant="normal">H</m:mi> </m:mrow> <m:mrow> <m:mn>4</m:mn> </m:mrow> </m:msub> </m:math> {{\rm{C}}}_{2}{{\rm{H}}}_{4} target, to an oxygen ion beam of 200 MeV/n is discussed. The charge identification is based on the controlled fading of nuclear emulsions in order to extend their dynamic range in the ionization response.