Particle separation for counter beams in the 100 GeV/c momentum range

Abstract

For the secondary particle intensities reached with the new proton-synchrotrons in the 100 GeV/ cmomentum range separation of kaons and antiprotons in counter experiments is interesting, even if a saturation range of a few 10 6 particles per pulse is considered. With the present-day technology only superconducting rf separators will provide a possibility of particle separation for momenta above 10 GeV/ c. The development of rf superconductivity will allow in the near future the use of superconducting niobium deflectors whose performances will be well adapted to the 100 GeV/ c momentum range. Unlike bubble chambers, counter systems do not need a high beam purity and the separation conditions can be relaxed, enabling for a given deflection higher acceptances and higher upper limits of separation. Some properties of superconducting deflectors are discussed and some guide-lines for the choice of parameters for a separator and for separated beams are given. It is shown that the upper limit for the working frequency of rf separators lies around 10 GHz (X-band). The rf separated beams are characterized by very small acceptances and momentum bites (a few μ rad, Δ p p = 1% ). Two possible rf separated beams with X-band separators for the CERN West experimental area and the extended North experimental area with a momentum range of 20–80 GeV/ c and 60–200 GeV/ c respectively are discussed. It is shown that with acceptances of a few μusr, a relative momentum bite of 1% and 10 12 interacting protons at the target a gain in wanted particle intensity with respect to an unseparated beam of the same momentum range well above 5 can be obtained.