An in-pile slow positron source was recently installed at the FRM research reactor of the Technical University of Munich. Neutron capture gamma rays of 113 Cd (n; γ) 114 Cd are converted into e+ - e- pairs by absorption in tungsten foils. Moderated positrons are emitted from the foil surface, accelerated by electric lenses to a few keV and guided to a remoderator outside the reactor pool by a magnetic solenoid. In a first approach the beam at the entrance of the remoderator yielded an intensity of 2.108 slow positrons per sec. The remoderator stage is already constructed and presently tested with electrons. The source will provide an order of magnitude more intensity when it will be installed at the FRM-II high flux reactor, which is under construction.    «

An in-pile slow positron source was recently installed at the FRM research reactor of the Technical University of Munich. Neutron capture gamma rays of 113 Cd (n; γ) 114 Cd are converted into e+ - e- pairs by absorption in tungsten foils. Moderated positrons are emitted from the foil surface, accelerated by electric lenses to a few keV and guided to a remoderator outside the reactor pool by a magnetic solenoid. In a first approach the beam at the entrance of the remoderator yielded an intensity...    »