A Differential Time-of-flight Spectrometer of Very Slow Neutrons
  A time-of-flight spectrometer of neutrons in the energy range (0.05 -- 2.5)$\mu$eV is described.   This spectrometer has been tested my measuring the total and differential neutron cross sections for a number of materials: Al, Cu, $^{6}$LiF, Si, Zr, teflon, polyethylene and liquid fluoropolymers, that are essential for experiments in the physics of ultracold neutrons. 
Yu.N. Pokotilovski, M.I. Novopoltsev, P. Geltenbort, Th. Brenner
nucl-ex cond-mat.other