The project of ultracold neutron sources at the PIK reactor with superfluid helium as a moderator

The project of ultracold neutron sources at the PIK reactor with superfluid helium as a moderator is presented. The rate of producing ultracold neutrons in superfluid helium is 100 cm^?3 s^?1 at neutron flux density Φ(λ = 9 Å) = 10⁹ cm^?2 s^?1 Å^?1. At a moderator temperature of 1 K within the experimental volume of 351, the density of ultracold neutrons may be equal to 1.3 × 10³ cm^?3, which is two orders of magnitude exceeds that the currently existing ultracold neutron sources.