MS13: Modelling and experimental verification of the new moderator concept

The goal of the exercise was to set up a Monte Carlo simulation tool for calculations of neutronics features of the current cold neutron source (CNS) at the Budapest Research Reactor (BRR) and experimental verification of source brightness parameters by measuring neutron yield in a “white beam” from the CNS at BNC, Budapest (HU) in order to design a new moderator configuration.  A provisional set up of direct beam measurement was prepared by using simple components to be able to perform time-of-flight data collection to get an intensity-wavelength dependence of the CNS at various cooling conditions. The experimental arrangement was set up at 8 m from the CNS just behind the heavy shutter of this beamline. A simple diaphragm – collimation – chopper – detector configuration was used. The cold source was cooled down at various conditions regarding the reactor power. The data and the report (neutron intensity as a function of the time starting from the reactor power ramp-up) are available upon request.