Schematic of test apparatus
Neutron Electric Dipole Moment Experiment
UIUC Test Facility
D. Beck, J. Blackburn, D. Hertzog, I. Hubler, P. Kammel, A. Kenyon, J.C. Peng, E. Thorsland
There are a number of experimental challenges associated with our measurement of the neutron EDM. The neutrons are trapped in superfluid L4He by the near perfect transfer of their energy and momentum to that of phonons in the fluid. The trap is held at a temperature of about 0.5 K (in order to minimize neutron losses at the walls). The neutron precession rate is measured via their interaction with polarized 3He which is introduced into the L4He at low concentrations. Among other things, we must generate a weak, uniform magnetic field and a very strong electric field; we must operate SQUIDS to monitor the magnetic field; we must be able to introduce highly polarized 3He into the L4He and then distill it out after it depolarizes; and we must be able to couple scintillation light from the the n-3He interactions outside the main experiment volume - all at 0.5 K!
In order to test some of these techniques, we are constructing a special low-temperature facility at UIUC. It will consist of a test volume cooled by pumping of both 4He and 3He vessels. The apparatus will be housed in a large 4He test dewar.
Schematic of test apparatus
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