Beam heating explains critical current suppression measured during ion irradiation of REBCO tapes
Reports of critical current (Ic) suppression during cryogenic ion irradiation of REBCO tapes have raised concerns for the operational margins of fusion power plant (FPP) magnets. However, the data remain inconclusive regarding beam heating due to the difficulty of measuring local temperatures wi...
| Main Authors: | , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
IOP Publishing
2024
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| Online Access: | https://hdl.handle.net/1721.1/157858 |
| _version_ | 1824457907574407168 |
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| author | Devitre, Alexis Fischer, David Riva, N. Rae, M. Kortman, Lauryn Woller, Kevin Fisher, Zoe Short, Michael Whyte, Dennis Hartwig, Zachary |
| author2 | Massachusetts Institute of Technology. Plasma Science and Fusion Center |
| author_facet | Massachusetts Institute of Technology. Plasma Science and Fusion Center Devitre, Alexis Fischer, David Riva, N. Rae, M. Kortman, Lauryn Woller, Kevin Fisher, Zoe Short, Michael Whyte, Dennis Hartwig, Zachary |
| author_sort | Devitre, Alexis |
| collection | MIT |
| description | Reports of critical current (Ic) suppression during cryogenic ion
irradiation of REBCO tapes have raised concerns for the operational margins
of fusion power plant (FPP) magnets. However, the data remain inconclusive
regarding beam heating due to the difficulty of measuring local temperatures
with contact probes. This leaves a critical knowledge gap concerning the
mechanism behind Ic suppression, and whether the so-called beam on effect is
to be expected under neutron irradiation during FPP operation. In this paper,
we show that Ic suppression is independent of atomic displacement rate in the
REBCO layer, the latter of which increases twelve-fold as we reduce the beam
energy from 2400 to 800 keV. At fixed power, we observe statistically identical
suppression with 150 keV protons, which do not have enough energy to reach
the REBCO layer, refuting hypotheses about beam on effects being caused by
nuclear displacements or direct ion-Cooper pair interactions. These results show
that REBCO temperature rise alone can explain Ic suppression, leaving little to no
margin for alternative mechanisms. With this insight, we developed a method to
measure beam spot temperature that does not depend on the specific installation
of our temperature sensor. With this new method, we measured the temperature
gradient across the tape during irradiation and found that thermal resistance at
the tape/target interface is the controlling variable in Ic suppression. As such,
accelerator-based facilities aiming to reproduce the operation of REBCO magnets
in a nuclear fusion environment should find strategies to minimize interface
thermal resistance. Most importantly, we find that the dose rates expected
in a FPP will not change Ic due to ballistic radiation damage or ion-Cooper
pair interactions, allowing us to safely ignore these effects when designing FPP
magnets. |
| first_indexed | 2025-02-19T04:17:27Z |
| format | Article |
| id | mit-1721.1/157858 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2025-02-19T04:17:27Z |
| publishDate | 2024 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1578582024-12-17T04:01:27Z Beam heating explains critical current suppression measured during ion irradiation of REBCO tapes Devitre, Alexis Fischer, David Riva, N. Rae, M. Kortman, Lauryn Woller, Kevin Fisher, Zoe Short, Michael Whyte, Dennis Hartwig, Zachary Massachusetts Institute of Technology. Plasma Science and Fusion Center Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Massachusetts Institute of Technology. Department of Materials Science and Engineering Reports of critical current (Ic) suppression during cryogenic ion irradiation of REBCO tapes have raised concerns for the operational margins of fusion power plant (FPP) magnets. However, the data remain inconclusive regarding beam heating due to the difficulty of measuring local temperatures with contact probes. This leaves a critical knowledge gap concerning the mechanism behind Ic suppression, and whether the so-called beam on effect is to be expected under neutron irradiation during FPP operation. In this paper, we show that Ic suppression is independent of atomic displacement rate in the REBCO layer, the latter of which increases twelve-fold as we reduce the beam energy from 2400 to 800 keV. At fixed power, we observe statistically identical suppression with 150 keV protons, which do not have enough energy to reach the REBCO layer, refuting hypotheses about beam on effects being caused by nuclear displacements or direct ion-Cooper pair interactions. These results show that REBCO temperature rise alone can explain Ic suppression, leaving little to no margin for alternative mechanisms. With this insight, we developed a method to measure beam spot temperature that does not depend on the specific installation of our temperature sensor. With this new method, we measured the temperature gradient across the tape during irradiation and found that thermal resistance at the tape/target interface is the controlling variable in Ic suppression. As such, accelerator-based facilities aiming to reproduce the operation of REBCO magnets in a nuclear fusion environment should find strategies to minimize interface thermal resistance. Most importantly, we find that the dose rates expected in a FPP will not change Ic due to ballistic radiation damage or ion-Cooper pair interactions, allowing us to safely ignore these effects when designing FPP magnets. 2024-12-16T20:28:50Z 2024-12-16T20:28:50Z 2024-12-02 Article http://purl.org/eprint/type/JournalArticle 1361-6668 https://hdl.handle.net/1721.1/157858 A R Devitre et al 2025 Supercond. Sci. Technol. 38 015005 en_US https://doi.org/10.1088/1361-6668/ad95c2 Superconductor Science and Technology Creative Commons Attribution-Noncommercial-ShareAlike Attribution-NonCommercial-ShareAlike 4.0 International http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf IOP Publishing Author |
| spellingShingle | Devitre, Alexis Fischer, David Riva, N. Rae, M. Kortman, Lauryn Woller, Kevin Fisher, Zoe Short, Michael Whyte, Dennis Hartwig, Zachary Beam heating explains critical current suppression measured during ion irradiation of REBCO tapes |
| title | Beam heating explains critical current suppression measured during ion irradiation of REBCO tapes |
| title_full | Beam heating explains critical current suppression measured during ion irradiation of REBCO tapes |
| title_fullStr | Beam heating explains critical current suppression measured during ion irradiation of REBCO tapes |
| title_full_unstemmed | Beam heating explains critical current suppression measured during ion irradiation of REBCO tapes |
| title_short | Beam heating explains critical current suppression measured during ion irradiation of REBCO tapes |
| title_sort | beam heating explains critical current suppression measured during ion irradiation of rebco tapes |
| url | https://hdl.handle.net/1721.1/157858 |
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