Real-time monitoring of the orthohydrogen fraction in a liquid hydrogen moderator

E. B. Iverson; B. D. DeGraff; J. J. Denison; B. W. Riemer; F. X. Gallmeier

doi:10.1016/j.nimb.2023.165176

Real-time monitoring of the orthohydrogen fraction in a liquid hydrogen moderator

E. B. Iverson, B. D. DeGraff, J. J. Denison, B. W. Riemer, F. X. Gallmeier

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

We present the first direct measurements of the orthohydrogen fraction in an operating liquid hydrogen moderator loop at a high powered neutron source. We have developed a Raman immersion probe capable of characterizing the orthohydrogen and parahydrogen makeup of a liquid hydrogen loop approximately every ten seconds, which can see orthohydrogen fractions lower than 0.20 without difficulty. At the Spallation Neutron Source, where the time-averaged power deposition in the studied moderator system is around 0.02 W/cm³, the orthohydrogen fraction increases with beam power and equilibrates at levels of 0.40, and responds to beam trips in a dynamic fashion. Additionally, we find that without deliberate catalyst systems in place, the relaxation due to the piping in the system has insignificant effect in catalyzing the relaxation of freshly condensed hydrogen toward thermodynamic equilibrium, and that the radiation levels associated with activation in a non-operating spallation neutron source target-moderator-reflector assembly likewise has insignificant effect on the liquid hydrogen kinetics.

Original language	English
Article number	165176
Journal	Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
Volume	547
DOIs	https://doi.org/10.1016/j.nimb.2023.165176
State	Published - Feb 2024

Funding

This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).Research sponsored by Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy. Work performed at Oak Ridge National Laboratory is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. Research sponsored by Oak Ridge National Laboratory , managed by UT-Battelle, LLC, for the U. S. Department of Energy. Work performed at Oak Ridge National Laboratory is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy . The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).

Funders	Funder number
DOE Public Access Plan
United States Government
U.S. Department of Energy
Oak Ridge National Laboratory
UT-Battelle	DE-AC05-00OR22725

Keywords

Moderators
Neutron
Orthohydrogen
Parahydrogen
Spallation

Access to Document

10.1016/j.nimb.2023.165176

Cite this

@article{fceb047e0a324331af74eea242f881e5,

title = "Real-time monitoring of the orthohydrogen fraction in a liquid hydrogen moderator",

abstract = "We present the first direct measurements of the orthohydrogen fraction in an operating liquid hydrogen moderator loop at a high powered neutron source. We have developed a Raman immersion probe capable of characterizing the orthohydrogen and parahydrogen makeup of a liquid hydrogen loop approximately every ten seconds, which can see orthohydrogen fractions lower than 0.20 without difficulty. At the Spallation Neutron Source, where the time-averaged power deposition in the studied moderator system is around 0.02 W/cm3, the orthohydrogen fraction increases with beam power and equilibrates at levels of 0.40, and responds to beam trips in a dynamic fashion. Additionally, we find that without deliberate catalyst systems in place, the relaxation due to the piping in the system has insignificant effect in catalyzing the relaxation of freshly condensed hydrogen toward thermodynamic equilibrium, and that the radiation levels associated with activation in a non-operating spallation neutron source target-moderator-reflector assembly likewise has insignificant effect on the liquid hydrogen kinetics.",

keywords = "Moderators, Neutron, Orthohydrogen, Parahydrogen, Spallation",

author = "Iverson, {E. B.} and DeGraff, {B. D.} and Denison, {J. J.} and Riemer, {B. W.} and Gallmeier, {F. X.}",

note = "Publisher Copyright: {\textcopyright} 2023",

year = "2024",

month = feb,

doi = "10.1016/j.nimb.2023.165176",

language = "English",

volume = "547",

journal = "Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms",

issn = "0168-583X",

publisher = "Elsevier",

}

TY - JOUR

T1 - Real-time monitoring of the orthohydrogen fraction in a liquid hydrogen moderator

AU - Iverson, E. B.

AU - DeGraff, B. D.

AU - Denison, J. J.

AU - Riemer, B. W.

AU - Gallmeier, F. X.

PY - 2024/2

Y1 - 2024/2

N2 - We present the first direct measurements of the orthohydrogen fraction in an operating liquid hydrogen moderator loop at a high powered neutron source. We have developed a Raman immersion probe capable of characterizing the orthohydrogen and parahydrogen makeup of a liquid hydrogen loop approximately every ten seconds, which can see orthohydrogen fractions lower than 0.20 without difficulty. At the Spallation Neutron Source, where the time-averaged power deposition in the studied moderator system is around 0.02 W/cm3, the orthohydrogen fraction increases with beam power and equilibrates at levels of 0.40, and responds to beam trips in a dynamic fashion. Additionally, we find that without deliberate catalyst systems in place, the relaxation due to the piping in the system has insignificant effect in catalyzing the relaxation of freshly condensed hydrogen toward thermodynamic equilibrium, and that the radiation levels associated with activation in a non-operating spallation neutron source target-moderator-reflector assembly likewise has insignificant effect on the liquid hydrogen kinetics.

AB - We present the first direct measurements of the orthohydrogen fraction in an operating liquid hydrogen moderator loop at a high powered neutron source. We have developed a Raman immersion probe capable of characterizing the orthohydrogen and parahydrogen makeup of a liquid hydrogen loop approximately every ten seconds, which can see orthohydrogen fractions lower than 0.20 without difficulty. At the Spallation Neutron Source, where the time-averaged power deposition in the studied moderator system is around 0.02 W/cm3, the orthohydrogen fraction increases with beam power and equilibrates at levels of 0.40, and responds to beam trips in a dynamic fashion. Additionally, we find that without deliberate catalyst systems in place, the relaxation due to the piping in the system has insignificant effect in catalyzing the relaxation of freshly condensed hydrogen toward thermodynamic equilibrium, and that the radiation levels associated with activation in a non-operating spallation neutron source target-moderator-reflector assembly likewise has insignificant effect on the liquid hydrogen kinetics.

KW - Moderators

KW - Neutron

KW - Orthohydrogen

KW - Parahydrogen

KW - Spallation

UR - http://www.scopus.com/inward/record.url?scp=85179085466&partnerID=8YFLogxK

U2 - 10.1016/j.nimb.2023.165176

DO - 10.1016/j.nimb.2023.165176

M3 - Article

AN - SCOPUS:85179085466

SN - 0168-583X

VL - 547

JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

M1 - 165176

ER -

Real-time monitoring of the orthohydrogen fraction in a liquid hydrogen moderator

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Cite this