Upgrading scientific capabilities of the neutron interferometer in NPI Rez

Recently, the neutron interferometer set-up installed at NPI Rei has been r econstructed in order to improve the quality of the experimental results an d to enlarge its flexibility for solving a wider rang of physical problems. A new sample holder permits to position, to rotate in a horizontal plane a nd tilt the sample in both beams inside the interferometer. The upgraded in terferometer facility was tested by measuring the very sensitive coherent s cattering length of Si performed by a nondispersive phase difference method . The result of this experiment is in very good agreement with the results obtained from the measurements carried out in HMI Berlin and NIST Gaithersb urg. It shows that the coherent scattering length can be measured using our instrument with a relative uncertainty of 0.002%. (C) 2000 Elsevier Scienc e B.V. All rights reserved.