TY - JOUR
T1 - Neutron diffraction from macroscopic objects and transverse coherence of the wavefunction: The Fresnel zone plates
AU - Altissimo, Matteo
AU - Petrillo, Caterina
AU - Sacchetti, Francesco
AU - Sani, Elisa
AU - Stahn, Jochen
PY - 2008
Y1 - 2008
N2 - A new high resolution (400 nm) Fresnel Zone Plate (ZP) of 1 mm diameter has been designed and produced in order to accurately measure its spatial resolution and efficiency. This experiment is an extension of the previous tests performed to measure the efficiency of these devices. The measurements were carried out on the diffractometer Morpheus at PSI using a new ZP designed to obtain a small focal length of 0.833 m at 4.7 (A) over circle. In this experiment a 0.8 mm edge square neutron source at 4.7 (A) over circle was demagnified by the ZP by a factor 2 down to about 0.4 mm at 1.24 m distance from the ZP. With this configuration, using a Gd knife edge, we determined the transverse profile of the image with a spatial accuracy of 0.01 mm. In addition an appropriate configuration was used to measure the efficiency of the ZP, which was equal to 0.28 +/- 0.02, to be compared to 0.325, that is the ideal value at 4.7 (A) over circle. The result for the ZP resolution suggests that the image has a broadening in the range of 0.01 mm, corresponding to an effective wave front coherence over a distance greater than 50 mu m, to be compared to some 0.2 mu m as deduced from the indetermination principle, according to the beam divergence. Numerical simulations of the ZP are performed with a partially coherent wave front to show the effect of the phase variation on the intensity at different positions. (c) 2008 Elsevier B.V. All rights reserved.
AB - A new high resolution (400 nm) Fresnel Zone Plate (ZP) of 1 mm diameter has been designed and produced in order to accurately measure its spatial resolution and efficiency. This experiment is an extension of the previous tests performed to measure the efficiency of these devices. The measurements were carried out on the diffractometer Morpheus at PSI using a new ZP designed to obtain a small focal length of 0.833 m at 4.7 (A) over circle. In this experiment a 0.8 mm edge square neutron source at 4.7 (A) over circle was demagnified by the ZP by a factor 2 down to about 0.4 mm at 1.24 m distance from the ZP. With this configuration, using a Gd knife edge, we determined the transverse profile of the image with a spatial accuracy of 0.01 mm. In addition an appropriate configuration was used to measure the efficiency of the ZP, which was equal to 0.28 +/- 0.02, to be compared to 0.325, that is the ideal value at 4.7 (A) over circle. The result for the ZP resolution suggests that the image has a broadening in the range of 0.01 mm, corresponding to an effective wave front coherence over a distance greater than 50 mu m, to be compared to some 0.2 mu m as deduced from the indetermination principle, according to the beam divergence. Numerical simulations of the ZP are performed with a partially coherent wave front to show the effect of the phase variation on the intensity at different positions. (c) 2008 Elsevier B.V. All rights reserved.
UR - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=000253845300015
M3 - Article
VL - 586
SP - 68
EP - 72
JO - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment
SN - 0168-9002
IS - 1
ER -