skip to main content NIST Center for Neutron Research NIST Center for Neutron Research National Institute of Standards and Technology
Home Reflectometry Instruments NG1REFL SiteMap

NG7 HORIZONTAL NEUTRON REFLECTOMETER

Picture of Horizontal Reflectometer
THE REFLECTOMETER

- Instrument Features
- Reflectivity Formalism
- Instrument Schedule
- Getting Beamtime

RESEARCH

- Publications
- Polymer Surfaces
- Biology

DATA ANALYSIS

- Overview
- Download ReflPak
- SLD Calculator



Neutron reflectometry is a relatively new technique for investigating the near-surface structure of many materials. Specifically, it probes the neutron scattering density at depths of up to several thousand Å, with an effective depth resolution of a few Å. What is measured is the profile of reflectivity as a function of angle beyond the critical angle for total external reflection. The sample must thus present a smooth, flat surface, preferably several cm2 in area. The method is extensively used for studies of polymer surfaces, Langmuir-Blodgett films, and thin films and multilayers of metals and semiconductors, both magnetic and non-magnetic.

The cold neutron reflectometer permits routine measurement of reflectivities as low as 10-6 in typical run times of a few hours. As shown in the schematic drawing below, a pyrolytic graphite monochromator array deflects neutrons onto a horizontal sample surface at a shallow angle ofincidence. Reflected neutrons are measured by a detector after passing through an exit slit system.

Independent movement of both sample and detector allows measurement of off-specular scattering. A position-sensitive detector permits simultaneous measurement of specular and off-specular scattering.


Instrument Scientists

Sushil Satija (301) 975-5250 satija@nist.gov
Guangcui Yuan (301) 975-5098 guangcui.yuan@nist.gov

Last modified 27-January-2015 by website owner: NCNR (attn: )