Monte-Carlo simulation of phase space transformation of ultra-cold neutrons

摘要

The very high phase space density of ultra-cold neutrons (UCN) originating from a superthermal UCN-source can be exploited for the production of intense cold neutron beams. UCN are accelerated by means of Doppler-shifter crystals. This method is called phase space transformation (PST). In the cold regime, gain factors of 100 are theoretically expected compared to standard beam generation. The Atominstitut in Vienna and the Paul Scherrer Institut have joined to design and construct a "proof of principle"-experiment for such a phase space transformer in the framework of the FP7-NMI3-JRA3 European project. The aims of this experiment are to explore its feasibility, its experimental limitations and to validate preceding MC-simulations. Employing a sophisticated mechanical system, stage-2 Potassium intercalated HOPG crystals (d = 8.74 A) will be moved with velocities of up to 250 m/s. The experiment is planned to take place at the PF-2 UCN source at the Institut Laue-Langevin (ILL) in the second half of 2007. In this contribution recent results of preliminary Monte-Carlo simulations of the experiment are presented.