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Experimental integration & commissioning

UCNτ — Neutron Lifetime Experiment

Experimental infrastructure, vacuum-system operations, detector installation, beamline readiness, diagnostic development and commissioning support for the magneto-gravitational neutron-lifetime experiment at LANL.

VacuumRigging / CraneDetector IntegrationUtilitiesDiagnosticsCommissioning

UCNτ+ apparatus during installation and commissioning

What is UCNτ?

A magneto-gravitational trap for measuring the free-neutron lifetime

UCNτ stores polarized ultracold neutrons in an asymmetric, open-top trap lined with a Halbach array of permanent magnets. The magnetic field repels weak-field-seeking neutrons from the trap surface while gravity confines them vertically, reducing losses from contact with material walls during storage.

After a controlled storage interval, a movable in-situ detector known as the dagger is lowered into the trap to count surviving neutrons. Comparing surviving populations after different storage times provides a measurement of the neutron lifetime.

UCN detector lowered above the Halbach array during a detector test — View into the magneto-gravitational trap with a UCN detector positioned above the Halbach array during detector testing.

Labeled CAD of the UCNτ Halbach array, dagger, cleaner, UCN guide and trap door — UCNτ storage trap showing the Halbach array, movable dagger detector, cleaner, UCN guide and original trap-door loading geometry.

How UCNτ works

Fill, store, then count the survivors

Fill & polarize

Ultracold neutrons are transported through the beamline, polarized and directed into the storage apparatus. Beamline monitors and detectors provide information about the delivered UCN population.

UCNτ beamline overview showing polarizer, spin flipper, detectors and Halbach array

Store without material-wall losses

The permanent-magnet Halbach array creates a strong magnetic boundary while gravity closes the trap vertically. The goal is to store UCN while minimizing non-decay losses associated with material bottle walls.

Schematic geometry of the UCNτ Halbach permanent-magnet array

UCN trajectories above the UCNτ Halbach permanent-magnet array

Count with the dagger

After the selected storage time, the dagger is lowered into the trap. Neutrons captured in the detector produce scintillation light that is carried through wavelength-shifting fibers to photomultiplier tubes for counting.

UCNτ dagger detector showing boron zinc sulfide strips, wavelength-shifting fibers and PMTs

My role

Experimental integration, facility support & commissioning

I supported UCNτ by bringing electrical power, compressed air and gas utilities to the experiment; performing major vacuum-chamber operations and crane lifts; supporting dagger installation and beamline connection readiness; and helping bring new hardware into an operable experimental configuration. I also developed a custom IR-camera diagnostic fixture to investigate vibration during trap motion and helped a student get started with image cleanup and object-identification methods for motion analysis.

Build-to-operations progression

From facility interfaces to the UCNτ+ elevator upgrade

My work centered on the physical interfaces that allowed the experiment and its upgrades to be installed, evacuated, connected, tested and handed over for operation.

Stage01

Facility utilities & experiment readiness

I brought electrical power, compressed air and gas services to the experiment and supported the practical interfaces required to connect UCNτ to the surrounding UCN facility. This included preparing for beamline connection and coordinating the hardware, access and utility needs around experimental work.

Stage02

Vacuum-chamber operations, rigging & detector installation

I supported major vacuum-chamber operations and crane lifts around the apparatus, including work required to access the trap and install experimental hardware. I also supported installation of the movable dagger detector and readiness for reconnection to the UCN beamline.

UCNτ Halbach trap with dagger detector visible — Inside the magneto-gravitational trap with the dagger detector positioned above the Halbach array.

Back of UCNτ dagger showing wavelength-shifting fibers and PMTs — Dagger optical readout: wavelength-shifting fibers carry scintillation light to PMTs.

Stage03

Custom IR motion diagnostic

To investigate vibration observed during trap motion, I built a custom diagnostic fixture that positioned an infrared camera over an existing ConFlat viewport. The 3D-printed fixture incorporated the camera, IR illumination and heat sinking so the moving hardware could be observed without opening the vacuum system. I also helped a student get started with basic image-cleanup and object-identification approaches for extracting motion from the recorded imagery.

Diagnostic approach: observe the mechanism through an existing vacuum viewport → stabilize camera / illumination geometry → collect motion imagery → clean frames and identify the moving object → use the visual record to support mechanical troubleshooting.

Stage04

UCNτ+ elevator / vacuum-extension upgrade

The UCNτ+ upgrade replaced the original loading approach with a movable UCN loading volume — an “elevator” — intended to improve transfer of ultracold neutrons into the magnetic trap. The upgrade added substantial new vacuum and mechanical hardware above the existing experiment.

CAD of UCNτ+ loading volume elevator above the Halbach array — UCNτ+ concept showing the new loading volume / elevator, filling guide and existing Halbach array.

Stage05

Mechanical fitting, craning & commissioning the upgrade

I performed extensive crane operations and fitting work while the UCNτ+ elevator and vacuum extension were installed and commissioned. The work required repeatedly positioning large hardware around the existing apparatus, establishing the new mechanical and vacuum interfaces, and supporting the team as the upgrade moved from installation into functional checkout.

UCNτ+ elevator and vacuum extension during installation — UCNτ+ installation showing the scale of the elevator / vacuum-extension hardware above the existing experiment.

Interior of the UCNτ+ vacuum extension during installation — Inside the open UCNτ+ vacuum extension during installation and commissioning.

Stage06

Operational handoff & experiment support

Across the original apparatus and later upgrade work, my role was to make sure the physical experiment was ready to operate: utilities available, vacuum and mechanical interfaces assembled, major hardware safely moved and installed, detector / beamline connections ready, and commissioning problems worked through with the experiment team.

Publication note

UCNτ technical record

I have not identified a UCNτ neutron-lifetime publication that lists me as an author. The UCNτ papers and presentations on the Sources page are therefore used as project references, not represented as my publications. My verified UCN detector coauthorship is listed with the broader UCN facility work and on the Publications page.