NOD - Neutron Optics Diffractometer

The Neutron Optics Diffractometer is a testing beamline installed on the common primary beam shared with the SANS diffractometer MAUD. Experimental investigations at this instrument are focused at experimental studies and tests of new Bragg diffraction optics designs and their properties. Recent examples are the tests of dispersive double crystal settings providing high and ultra-high angular and/or energy resolution and of ultra-high resolution dispersive monochromators based on multiple reflections excited in elastically deformed perfect crystals. The high-resolution monochromatic neutron beams also opened new possibilities of applications for an alternative radiography technique, for the so called phase contrast radiography.

Instrument description

NOD is a three axis diffraction instrument designed primarily for experiments with Bragg diffraction optics. It is equiped with a bent Si(111) crystal as a pre-monochromator in a monochromator shielding cave and other two optical axes, which are freely accessible for experiments (2θ-arm, two rotating tables and four goniometer heads for a sample and an analyzer). Furthermore, the instrument is equipped with an Eulerian cradle of the inner diameter of 400 mm.

The pre-monochromator has a fixed take-off angle of 30o, providing monochromatic neutrons at the wavelength of 0.162 nm. The instrument shares the reactor beam channel with the small angle scattering instrument MAUD, which selects another wavelength from the same primary beam.

Instrument parameters

Monochromator   bent perfect crystal Si(111), symmetric reflection
Sample maximum irradiated cross-section 4x25 mm2
Analyzer bent perfect crystal Si(111), Si(220), Si(311) etc.
Detectors - single 3He counter, diameter 1/2''
- 1D dimensional position sensitive detector, 3He filled, resolution ~ 2 mm
- Imaging plate with the resolution 50 x 50 μm.
Wavelength 1.62 Ă
Neutron flux 5x104 n s-1 cm-2

Request for beam time

All external users need to request beam time via the proposal system. Instruments installed in the LVR15 reactor hall have become a part of the CANAM (Center of Accelerators and Nuclear Analytical Methods) infrastructure. The Open access for the CANAM instruments is available for all users via the web based proposal system on the User portal web page. In order to submit experimental proposal, please, register (or login) to CANAM user office web site. The proposals are evaluated by our international Scientific selection panel and, when accepted, a corresponding beamtime is ascribed to the proposal. Unlike the other similar laboratories in Europe, we evaluate the proposals on a continuous basis (which means that there is no deadline and the beamtime allocation is in reasonably short time for the successful proposals). Usually, the proposals will be evaluated soon, possibly within a few weeks after being submitted. In case of positive evaluation the date of experiment beam time can be discussed with instrumental responsible. It is recommended to discuss the feasibility of your proposed experiment with the instrumental responsible (Pavol Mikula - before final submiting of the proposal.