200 mm f 58 Ni 99% specular guide

200 mm f DLC 50% diffuse “T” 65.5 mm f DLC 99% specular guides Cu gap 100% diffuse SS flange 200 mm f 58Ni 99% specular guide Stopping UCN positions SD2

Flapper SD2 Stopping UCN positions

Stopping UCN positions First bend 90% specular DLC Cu gaps

Pump-out port and gate valve 1 90% specular DLC Entrance to gate valve 2

Stopping UCN positions 65.5 mm f Entrance to GV 2 4.87+/-0.04x10-9 UCN/p 100% polarized PPM Magnetic field region Al window and fixture 6.4 mm f Monitor hole 1 3.1+/-0.1x10-10 UCN/p 6.4 mm f Monitor hole 2 2.0+/-0.3x10-11 UCN/p

Where do the UCN go?(flapper obstruction not simulated) Lost in the SD2 45.12% Lost in the vertical guides 42.32 Lost in the SS flange 5.15 Lost in the DLC guides before the Al window 2.71 Lost in the Cu gaps 0.86 Lost in the Al window 0.56 Lost in the DLC guides after the Al window 0.07 Leaks and numerical losses 0.04 Still in the system* (at 240 s) 0.83 Exited the monitoring holes 0.15 Arrived at gate valve 2 2.19 100.0 * System defined out to gate valve 2

200 mm f 58 Ni 99% specular guide