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@INPROCEEDINGS{Maharaj:1031239,
author = {Maharaj, Dalini and Li, Jingjing and Baggemann, Johannes
and Rücker, Ulrich and Zakalek, Paul and Gutberlet, Thomas},
title = {{TOWARDS} {THE} {DEVELOPMENT} {OF} {A} {COMPACT} {VERY}
{COLD} {NEUTRON} {SOURCE} {FOR} {THE} {HIGH} {BRILLIANCE}
{NEUTRON} {SOURCE}},
reportid = {FZJ-2024-05627},
year = {2024},
abstract = {Very cold neutron (VCN) sources present an exciting
opportunity for scientists to access unprecedented length
and time scales, and achieve improved sensitivity in neutron
experiments [1]. VCNs are defined over a wide spectral
range, from 1 meV (9 Å) down to a few hundred neV (>
several 100 Å). Wavelengths of up to several tens of Å are
of particular interest to many research communities.
Recently, thermal scattering kernels were developed for
candidate VCN moderator and reflector materials under the
HighNESS project [2]. These advances present an opportunity
for the conceptual design of VCN sources at newly emerging
high-current compact accelerator-driven neutron sources
(Hi-CANS). The High Brilliance neutron Source (HBS) is a
Hi-CANS project which hosts a linear accelerator delivering
a pulsed proton beam of energy, 70 MeV, and peak current,
100 mA, to a novel high-power tantalum target and compact
target-moderator-reflector (TMR) [3]. A low-dimensional
parahydrogen cold moderator has already been designed for
the HBS and tested at the JULIC Neutron Platform. Starting
from this concept, a Monte Carlo study is underway to
develop a target moderator reflector (TMR) to realise a very
cold neutron source for the HBS. The low dimensional
parahydrogen moderator will serve as an efficient cold
neutron converter, and within it, an appropriate secondary
moderator is implemented to shift the neutron spectrum
generated by the parahydrogen to lower energies, or
equivalently longer wavelengths. As methane is known to
generate a colder neutron spectrum than parahydrogen, it is
currently being investigated to shift the cold spectrum of
parahydrogen to lower energies. Figure 1 a.) shows a
geometry with parahydrogen only and that with methane
embedded in parahydrogen. Figure 1 b.) clearly shows that
methane shifts the spectrum to lower energies. Results from
a full optimization of this moderator-reflector geometry
conducted in PHITS shall be presented. [1] J.M Carpenter and
B.J. Micklich, ANL (05/42) (2005).[2] V. Santoro et al,
(2023). Nuclear Science and Engineering, 198 31–63
(2023)[3] T. Brückel, T. Gutberlet (Eds.), Conceptual
Design Report Jülich High Brilliance Neutron Source, ISBN
978-3-95806-501-7 (Forschungszentrum Jülich, 2020).},
month = {Sep},
date = {2024-09-24},
organization = {13th Design and Engineering of Neutron
Instruments MeetingDENIM XIII, JAEA
Tokai Mirai Base, Tokai, Ibaraki
(Japan), 24 Sep 2024 - 30 Sep 2024},
subtyp = {Invited},
cin = {JCNS-2 / JCNS-HBS / JARA-FIT},
cid = {I:(DE-Juel1)JCNS-2-20110106 / I:(DE-Juel1)JCNS-HBS-20180709
/ $I:(DE-82)080009_20140620$},
pnm = {632 - Materials – Quantum, Complex and Functional
Materials (POF4-632) / 6G4 - Jülich Centre for Neutron
Research (JCNS) (FZJ) (POF4-6G4)},
pid = {G:(DE-HGF)POF4-632 / G:(DE-HGF)POF4-6G4},
typ = {PUB:(DE-HGF)24},
url = {https://juser.fz-juelich.de/record/1031239},
}