Simulation Project SANS-2: The source-guide system

The SINQ cold source is made from liquid deuterium, D\(_2\). The outgoing neutrons are not brought into complete thermal equilibrium with the cold source, so the energy/wavelength spectrum is not completely Maxwellian. However, it can be described as a sum of three Maxwellians. This is implemented in the source component source_maxwell_3. The correct parameters for this component are

 width=0.085, height=0.16, T1=150.42, T2=38.74, T3=14.84,
 I1=3.67E11, I2=3.64E11, I3=0.95E11

The opening in the biological shielding, which we use for the SANS-2 beam port, is 0.050 m high and 0.050 m wide and starts 1.5 m from the cold source, which is 0.08 m wide and 0.16 m tall.

The SANS-2 guide system first has a 4.5 m long straight section. Then follows a 20 m curved section made from 40 0.5 m straight pieces, placed so that the radius-of-curvature is 2.4 km, then a 10 m long straight guide. However, here we make the simplification that the guide is straight and is in one piece.

The guide material has \(m=2\) with same parameters as in the simulation problem A neutron guide system . The guide has measures 0.05 m times 0.05 m along its whole length.

Update your simulation of the guide system and measure the wavelength and energy spectrum at the end of the guide. You can neglect neutrons with a wavelength below 1 Å (corresponding to an energy above 82 meV).