München 2019 – wissenschaftliches Programm
HK 14.5: Vortrag
Montag, 18. März 2019, 17:45–18:00, HS 11
Towards the final setup of KOALA experiment — •Yong Zhou and Huagen Xu — Institute for Nuclear Physics (IKP), Forschungszentrum Jülich, Germany
The KOALA experiment will measure antiproton-proton elastic scattering cross-section in a wide range of four momentum transfer |t| from 0.0008 to 0.1 (GeV/c)2 at the upcoming HESR ring of FAIR. It aims to provide key input parameters for PANDA’s luminosity determination. The recoil detector of KOALA has already been built and tested with proton beams by measuring proton-proton elastic scattering at COSY. The recoil detector measures both the kinetic energy and the polar angle of the recoil proton. The beam test results show that a range of |t| down to 0.001 (GeV/c)2 can be measured with the recoil detector alone. However, large background events from inelastic proton-proton reaction at polar angle close to 90∘ limit the ability of the recoil detector to reach all the way down to the lowest end of the required |t| range. To extend the lower limit, a forward scintillator detector has been built. The goal is to suppress the high background by the coincidence measurement between the recoil proton and the forward scattered beam particle. The scintillator bars are placed close to the beam axis covering the polar angle range of 0.4∘-1.2∘. Performance tests of the forward detector are carried out in the laboratory and the results will be reported in this talk. The commissioning of the full KOALA setup with proton beam at COSY is also described and the latest results will be presented.