Facility systems

Ultracold Neutron Facility Systems

The UCN facility converts high-energy spallation neutrons into ultracold neutrons that can be transported through guides and stored for precision experiments.

UCN sourceBeamlinesVacuumCryogenicsMagnetsControls

What does the facility do?

Turning an 800 MeV proton beam into ultracold neutrons

LANSCE protons strike a tungsten spallation target to create energetic neutrons. Successive moderator stages reduce their energy, and a solid-deuterium converter at cryogenic temperature produces the ultracold-neutron population used by experiments in Area B.

Unlike a single experiment, the UCN source and beamline are shared infrastructure: they produce, condition and transport neutrons to experiments such as nEDM, UCNτ and UCNA/B.

Diagram showing neutron moderation and ultracold-neutron production at the LANL UCN source — UCN production chain from the LANSCE proton beam through tungsten spallation, moderation and the cryogenic solid-deuterium converter.

Production chain

From accelerator beam to experiments

800 MeV protonsLANSCE accelerator beam

SpallationTungsten target produces energetic neutrons

ModerationBe / graphite and polyethylene reduce neutron energy

UCN conversionSolid D₂ at cryogenic temperature

BeamlinesUCN transported to Area B experiments

Area B context

One source supporting multiple precision experiments

Area B CAD showing UCN source, beamlines and experiments — UCN source, north and west beamlines, polarizing magnets and major experiments.

Photograph of Area B — Experimental-area view for scale and physical context.

My role

Supporting the systems between the source, facility and experiments

My responsibilities spanned nitrogen and helium distribution, helium-liquefier operation, superconducting-magnet support, vacuum pumping on primary UCN beamlines, deuterium-gas infrastructure, PLC/HMI controls, beamline pressure and temperature instrumentation, experimental-user integration and general facility hardware support.

I also supported accelerator beamline work upstream of the UCN source. I participated in dismantling, repair and reinstallation of approximately 50 ft of Line B, installed fixed beamline components and additional temperature/pressure instrumentation, and integrated those signals into DAQ, online monitoring and the Central Control Room (CCR). The work required coordination with Accelerator Operations, the target, vacuum, controls, water and fabrication teams, Industrial Hygiene and Radiation Protection, including radiological hot-work controls and active total-dose monitoring.