Development of a perfect crystal neutron accumulator

The basic principles of a perfect crystal storage system have been demonstrated during the last decade. Monochromatic neutrons can be trapped between perfect crystal plates and within a neutron guide for over 4 seconds which corresponds to more than 2000 back- and forth-reflections within a one meter long storage system. The related instrument has been installed at the ISIS neutron spallation source and it has been improved step by step towards a neutron resonator system. It also represents an essential part of an EU financed TMR-Network. In order to overcome intrinsic limitations of the excifing system, a new system should be developed which opens a perspective towards a neutron accumulator system where many neutron pulses from the source can be stored simultaneously reaching a flux density according to the peak flux of the source. The new system will use a pulsed neutron magnetic resonance system between the crystal plates instead of pulsed fields applied to the crystals, thus pulsing a low power hf-field instead of a strong 1.2 T field, which causes unavoidable losses due to induced vibrations. Vibrations from the ground have to be damped as well, because any vibrations cause reflectivity losses of stored neutrons. The objective of this project is to store more than 20 pulses simultaneously and to reach a quality factor Q > 104 . Such systems are capable for advanced neutron beam tailoring methods which could increase the performance of pulsed spallation sources considerably. In these cases very short neutron burst or pulsed systerm with variable repetition rates can be established. Basic experiments concerning the Zeno-effect or phase space cooling become feasible which are part of this proposal.