{"id":15,"date":"2007-10-04T19:47:54","date_gmt":"2007-10-05T00:47:54","guid":{"rendered":"http:\/\/www.fruechtetheory.com\/blog\/2007\/10\/04\/analysis-of-klein-a-g-and-werner-s-a-neutron-optics-rep-prog-phys-vol-46-1983\/"},"modified":"2007-10-04T19:47:54","modified_gmt":"2007-10-05T00:47:54","slug":"analysis-of-klein-a-g-and-werner-s-a-neutron-optics-rep-prog-phys-vol-46-1983","status":"publish","type":"post","link":"https:\/\/www.fruechtetheory.com\/blog\/2007\/10\/04\/analysis-of-klein-a-g-and-werner-s-a-neutron-optics-rep-prog-phys-vol-46-1983\/","title":{"rendered":"Analysis of: Klein, A. G. and Werner, S. A., Neutron Optics, Rep. Prog. Phys., Vol. 46, 1983"},"content":{"rendered":"

As stated in the abstract, alluded to in the title, and reiterated throughout Klein and Werner, \u201cA range of phenomena similar or analogous to those of classical optics is exhibited by slow neutrons.\u201d\u00a0 The abstract goes on to say that this includes \u201creflection, refraction, diffraction and interference\u201d. \u00a0It would not be possible for neutrons to have wave characteristics which behave like massless photons in most ways, no matter their velocity, if they were affected by gravity.
\nAttempts are made in the paper to insert Newtonian gravity, however calculations make use of the quantum in the main.\u00a0 Additionally, the effect of gravity, as an experiment that is rotated, is given in terms of phase shift.\u00a0 With wavelengths on the order of Angstroms, it is easy to see that phase will be effected by the gravitational force acting on parts in the test apparatus, in terms of tension, compression, shear, and bending.
\nThere are two experiments referenced in the paper that attempt to include the effect of the Earth\u2019s gravitational field.\u00a0 In the first, Koester 1965, 1967, as in Dabbs et al, there is a straight path to the neutron sensor after single edge diffraction, in this case at \u201cK5\u201d [p. 282] [2.7.2<\/em> Measurements of scattering lengths based on mirror reflection<\/em>.]
\n\u201cIn the very first neutron interferometer, built by Maier-Leibnitz and Springer (1962) (see figure 19(a))\u201d, the flight path spans 9.5 meters, dimension D in the figure.\u00a0 \u201cThe mean effective wavelength was 4.4 \u01fa\u201d, which corresponds to a velocity of 899 m\/s.\u00a0 Neglecting travel through the prism, a drop of 551 \u03bcm would be expected due to a gravitational acceleration of 9.81 m\/s2<\/sup> .\u00a0 No such drop is mentioned, nor is an adjustment in location of the \u201cscanning slit\u201d mentioned.\u00a0 If the neutrons were pulled by gravity and coming in at an angle off horizontal, we would expect an effect on the interference pattern.\u00a0 The position of the \u201cmain slit\u201d [Fig. 19(b)] is varied only \u00b1 60 \u03bcm. [3.4.1<\/em> Interference by division of the wavefront<\/em>.]
\nIn the same section, with a different apparatus, [Fig. 20], \u201cKlein and Opat (1976)\u201d, there is a shorter flight path, 2.0 m, and a slower velocity, 20 \u01fa, 198 m\/s.\u00a0 Again, no compensation for gravity is shown, and the Fresnel diffraction pattern is implied as being the same as for light of a similar wavelength.\u00a0 This implication is supported by the main emphasis of the paper.
\nIn the section [3.4.2 Interference by amplitude division<\/em>], neutron interference is said to be \u201ctopologically similar to the Raleigh interferometer of classical optics\u2026 (Zeilinger 1981)\u201d, and also \u201canalogous to the Lummer-Gehrke interferometer of classical optics\u201d.\u00a0 Other types of experiments pointed out as being similar are \u201cband pass monochromators\u201d and \u201cthe so called \u2018super-mirrors\u2019 (Mezei 1976, 1978, Mezei and Dagleish 1977) which are highly efficient neutron polarizers.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

As stated in the abstract, alluded to in the title, and reiterated throughout Klein and Werner, \u201cA range of phenomena similar or analogous to those of classical optics is exhibited by slow neutrons.\u201d\u00a0 The abstract goes on to say that this includes \u201creflection, refraction, diffraction and interference\u201d. \u00a0It would not be possible for neutrons to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-15","post","type-post","status-publish","format-standard","hentry","category-neutron-experimentation"],"_links":{"self":[{"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/posts\/15","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/comments?post=15"}],"version-history":[{"count":0,"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/posts\/15\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/media?parent=15"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/categories?post=15"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fruechtetheory.com\/blog\/wp-json\/wp\/v2\/tags?post=15"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}