Status of the GRANIT Facility

Figure 14

Number of UCNs detected for 30 min versus the free fall height. During the measurement, the temperature of He-II was 1.35 K. Since the UCN spectrum is defined by the storage and transmission properties of the whole system, and the temperature of He-II affects only the total count rates, the exact value of the temperature is of no importance. This measurement was fitted with a Monte-Carlo simulation, assuming an initial triangular or Gaussian spectrum.