Cold neutron beams are guide tubes which feed a number of instruments with cold neutrons. These are produced by either the Vertical Cold Neutron source (VCN) or the Horizontal Cold Neutron (HCN). Cold neutrons are neutrons with a low energy (<10 meV), a long wavelength (>3 Å), a low speed (<1400 m/s). They are ideal for the study of slow dynamics, large scale structures, biological systems, etc.
HCN: H14, H15, H16, H17, H18, H112, H113; VNC: H511, H512, H52, H53
cryoEDM, D7, D11, D16, D17, D22, D33, Figaro, IN5, IN6, IN10, IN11, IN12, IN15, IN16, LADI III, PF1B, PF2, SuperADAM@H52, ThALES
Cold neutron guides are guides fed by the neutrons coming from a cold source. They are tubes whose interior is covered by nickel or by supermirrors and neutrons propagate by total reflection inside them.
They have two main functions:
- they lead the neutrons away from the cold neutron sources without significant loss. In this way, the number of instruments placed around the reactor can increase and the overall reactor cost per instrument is reduced.
- the sharper their curvature, the lower is the speed of neutrons (which means longer wavelengths) that are able to negotiate the bends. The transmitted beam is therefore cleaned of hindering short wavelength neutrons and the unbendable gamma radiation emitted by the core.