Master Thesis

IMPULSE-2019-00248

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Optimization of a Cylindrical Para-Hydrogen Moderator for Cold Neutrons

Haugeneder, M.

2019

Abstract: In this Master's thesis the properties of a small cylindrical para-hydrogenmoderator delivering cold neutrons is investigated using MCNP. It may be situatedwithin a regular beam tube of the FRM II.This work presents a separate optimization of both length and radius of thiscylindrical moderator and a theoretical description of the simulation results. It isfound that there is an optimum length, whereas the radius should be chosen independence of the experimental needs. In this case, as the total ux at thebackside of the cylinder is considered, it should be as big as possible. Furthermorethe spectral output of such a cold neutron source is investigated and a theoreticalinterpretation of the results is suggested.These results are compared to an ideal model of the existing cold source at theFRM II facility. It is found that a para-hydrogen moderator is capable of deliveringa higher neutron ux than the conventional cold source, which moderates neutronsby subsequent elastic scattering events. This is achieved by an inelastic collisionexciting the rotational transition in para-hydrogen.

Keyword(s): Instrument and Method Development (1st) ; Instrument and Method Development (2nd)

Note: Masterarbeit, TU München, 2019

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Contributing Institute(s):

1. UCN (UCN)

Experiment(s):

1. UCN source (SR6)

Appears in the scientific report 2019

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