The performance of magnetic lens for focusing VCN-SANS

Autor: Ken Haste Andersen, P. Geltenbort, Toshiji Kanaya, Shane J. Kennedy, Bruno Guerard, John M. Carpenter, Giuliana Manzin, Kenji Mishima, Hiromu Tongu, Katsuya Hirota, Masaaki Kitaguchi, Masahiro Hino, M. Ichikawa, Masako Yamada, Norifumi L. Yamada, Yoshihisa Iwashita, M. Bleuel, Jyotsana Lal, Hirohiko M. Shimizu
Rok vydání: 2011
Předmět:
Zdroj: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 634:S156-S160
ISSN: 0168-9002
Popis: We have developed a prototype rotating-permanent magnet sextupole lens (named rot-PMSx) for more efficient experiments with neutron beams in time of flight (ToF) mode. This lens can modulate the focusing strength over range 1.5 × 10 4 T / m 2 ⩽ g ′ ⩽ 5.9 × 10 4 T / m 2 . Synchronization between the modulation and the beam pulse produces a focused beam without significant chromatic aberration. We anticipate that this lens could be utilized in focusing small angle neutron scattering (SANS) instruments for novel approach to high resolution SANS. We carried out experiments testing the principle of this lens at the very cold neutron (VCN) beamline (PF2) at Institut Laue-Langevin (ILL), France. The focused beam image size at the detector was kept constant at the same beam size as the source ( ≈ 3 mm ) over a wavelength range of 30 A ⩽ λ ⩽ 48 A in focal length of ≈ 1.14 m . The flux gain was about 12 relative to a beam without focusing, and the depth of focus was quite large. These results show the good performance of this lens and the system. Thereupon we have demonstrated the performance of this test bed for high resolution focusing of VCN-SANS for a well-studied softmatter sample; a deuterium oxide solution of Pluronic F127, an (PEO)100(PPO)65(PEO)100 tri-block copolymer in deuterium oxide. The results of the focusing experiment and the focusing VCN-SANS are presented.
Databáze: OpenAIRE