C3-1-2 MINE
Neutron Reflectmeter/Multilayer Interferometer
Instrumental Overview
    A new cold neutron reflectometer and a multilayer interferometer have has been installed
at C3-1-2 beam port of JRR-3M reactor, as shown in Fig.1 [1,2].The reflectometer is utilized
for many applications over neutron optics,polymer thin films with lamellar structure and sur
-face physics since 1994[3,4].The multilayer interferometer will be utilized tentatively for
the investigations of the quantum mechanical behaviors of matter waves and the search of the
very weak interactions to neutrons since 1995[5].
  Monochromatic incident neutrons for the reflectometer and the multilayer monochromator are
supplied from a multilayer monochromator system, which consists of four Ni-Ti multilayer mi-
rrors with reflectivity higher than 90 % arranged in a partial polygon as shown in Fig.1.
   Neutrons from the guide tube are monochromatized by four sequential Bragg reflections and
deflected by 23 degrees.  The incident neutrons  have a long wavelength of 12.6 A with wave-
length resolution of 3.2 %.Neutron intensity rediction due to the long wavelength is substan
tially compensated by relatively coarse beam divergent angle and wavelength resolution.
   The reflectometer has the advantage of large reflection angle which is appropriate to the
studies of low q and off-specular phenomena.The reflectometer is arranged in vertical geomet
-ry to yield a beam cross section of  3mm X 40mm and  applicable to a mirror system which is
formed on a flat substrate.Neutron detector system consists of a He-3 detector for q-2q scan
-ning and a position sensitive detector for measurement of off-specular profile.
 A typical intensity of 1000 counts/sec is available for reflectivity measurements.A reflect
-ivity curve is obtained within several hours  and reflectivity of 10-5 can be measured. The
performance of the instrument is comparable to other neutron reflectometers[6].The multilayer
interferometer  is a kind of Mach-Zehnder type interferometer for cold neutrons using multi-
layer mirrors  as optical elements,  which consists of a semitransparent mirror as a neutron
wave splitter, two reflection mirror and a semitransparent mirror as phase analyzer[7].  The
multilayer mirror must have  very hig perfection  and the four mirrors must  be aligned with
very high positional accuracy keeping strict stability.
 The multilayer interferometer is set up on an air cushion bench with a big granite base, in
a thermo-static chamber. The interferometer can not work simultaneously, while the reflecto-
meter runs.  Incident neutrons on the interferometer  are supplied easily by removing only a
few parts of the reflectometer.  Neutron beam is monitored by neutrons  transmitting through
through the third mirror of the monochromator system. A laser light beam can be used for ex-
perimental setup.

    	[1] T.Ebisawa, et al., Physica B (in press).
     	[2] T.Ebisawa, et al., Physica B (in press).
      	[3] S.Tasaki, et al., Physica B (in press).
       	[4] H.Funahashi et al., to be published.
	[5] T.Ebisawa, et al., Neutron Research (to be published).
	[6] M.Stamm, et al., Physica B 173 (1991) 11-16.
	[7] T.Ebisawa, et al., Nucl. Instr. and Meth. in Phys. Res. A 344, 1994, 597-606.

Contact person : Toru EBISAWA
	Reseach Reactor Institute,Kyoto University,
	Kumatori,Osaka 590-04

Return to Instrumentation
Return to ISSP-NSL home page
Return to ISSP home page