UCNA specs – JWM 9/4/7• Proton beam energy = 800 MeV• Peak proton current = 40 uA• Duty cycle = 1/10 (1 sec on, 10 sec off)• Therefore time-averaged current is 4 uA.• Source is designed to take 10 uA time-averaged.• Spallation target is tungsten, 2cm diameter, 10 cm long.

• Cooling of spallation target achieved by flowing compressed He gas.

• The length of the red “beta spectrometer” at bottom center of next slide is about 5.5 m long

• Shielding is 9’ of steel and 6’ of concrete.• People can walk around area when beam is on (provided shielding

is all in place)• Remote extraction handled by removing one shield block, then

pulling out a package from custom-made block. (see picture)

Thanks to M. Makela and A. Saunders from LANL for providing the numbers

Layout in Area B800 MeVprotons

UCNSource

beta-spectrometer

polarizermagnet

proton beamdirection

shield package

UCN port

remote extraction

UCNto expt

“prepolarizer” magnet

polarizer magnet

beta-spectrometer magnet

UCN guideinsertion

future UCNguide path

Status