Sonderkolloquium

From neutrons to positrons

Prof. Dr. Dirk Schwalm -- Max Planck Institute for Nuclear Physics, Heidelberg, and Weizmann Institute of Science, Rehovot, Israel

Already in 1990 Krusche and Schreckenbach [1] presented a concept to produce intense moderated positron beams using thermalized reactor neutrons. This idea was now realized at the FRM-II in Munich by Schreckenbach and his colleagues [2]. With >109 moderated positrons/s in a beam of <1 cm diameter NEPOMUC is presently the most intense positron source worldwide. The high intensity and brightness of the beam allows for a number of new experiments ranging from applications in materials science to high-sensitivity studies in surface and solid state physics up to fundamental investigations in plasma physics and the physics of positronium. A recently performed precision measurement of the lifetime of the negative positronium ion (e+e-e-) [3] will be used to exemplify these new possibilities.

[1] B. Krusche, K. Schreckenbach, NIM A295 (1990) 155[2] e.g. C. Hugenschmidt, C. Piochacs, M. Reiner, K. Schreckenbach, NJP 14 (2012) 055027[3] H. Ceeh, C. Hugenschmidt, K. Schreckenbach, S.A. Gärtner, P. Thirolf, F. Fleischer, D. Schwalm, Phys. Rev. A84 (2011) 062508

Optics with slow neutrons

Dr. Roland Gähler -- Institut Laue-Langevin, Grenoble, Frankreich

The VCN beam H18 at ILL, designed by Heinz Maier-Leibnitz, has evolved as a nucleus for new ideas on optics with slow neutrons, and many of these ideas had been worked out and brought to life in collaboration with TUM. The talk will report on successes and failures, missed opportunities and successful new developments. Finally I will sketch some visions of future neutron scattering instruments.

Please note the earlier starting time.