Design of a low-energy electrostatically-separated antiproton beam K4 at the KEK 12 GeV proton synchrotron

The beam K4 is designed to transport high-intensity, goodpurity antiprotons in the momentum range between 0.4 to 0.8 GeV/c. The beam shares its first half with the existing K3 beam for the purpose of saving the cost of the construction and shortening the time needed to develop the beam. Antiprotons and separated from unwanted particles (pions, muons and electrons) by double-stage mass separation. The solid-angle momentum acceptance of the beam is 34.1 msr% delta P/P and the beam length is 28.5 m. Seven hundred antiprotons per 1012 protons onto the 5 x 10 x 60 mm platinum target are expected at 600 MeV/c with the pi - mu -e- /p- ratio of less than ten. (author)