Neutron handling

The ultra-cold neutrons coming from the UCN source have to be guided into the experiment. This requires

  • guides with as few losses as possible,
  • valves to allow storage of UCN in the experiment,
  • and a beam splitter to switch between filling the experiment and emptying into a neutron detector.

Additionally, an absorbing ring is installed inside the storage volume to remove UCN with higher energies, that could not be stored magnetically. The absorber will be able to move up and down to investigate possible systematic effects depending on the neutron energy spectrum.

UCN polarization

The magnetic field of PENeLOPE can only store UCN with correct polarization. The other spin component has to be removed before the measurement.

The incoming UCN beam will be filtered while traversing a magnetized iron film. Their polarization is kept by a small magnetic field produced by several normal conducting coils.

Nevertheless, a small amount of wrongly polarized UCN will still be trapped inside the storage volume. These can be removed by moving down the absorber when the magnetic field is active.

UCN detector

After a certain storage time, the magnetic field is ramped down and the UCN are emptied into a neutron detector.

At the moment, it is planned to use a so-called CASCADE detector, which has been proven to detect ultra-cold neutrons with very high efficiency.