Upgrade of Super-Kamiokande with Gadolinium

Fuente: arXiv
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Main Authors: Koshio, Yusuke, Nakahata, Masayuki, Sekiya, Hiroyuki, Vagins, Mark R.
Format: Preprint
Published: 2025
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_version_ 1866908918560587776
author Koshio, Yusuke
Nakahata, Masayuki
Sekiya, Hiroyuki
Vagins, Mark R.
author_facet Koshio, Yusuke
Nakahata, Masayuki
Sekiya, Hiroyuki
Vagins, Mark R.
contents Super-Kamiokande [SK] was upgraded through the addition of gadolinium sulfate to its ultrapure water, initiating the SK-Gd program. This development enables efficient neutron tagging via the large capture cross section of gadolinium, greatly improving the identification of inverse beta decay events, the primary channel for detecting the diffuse supernova neutrino background [DSNB]. The upgrade also enhances sensitivity to galactic and pre-supernova neutrinos, as well as atmospheric neutrino interactions. To realize this capability, extensive work was performed, including the construction and operation of the EGADS demonstrator, the refurbishment of the SK tank, the development of radiopure gadolinium production methods, and the validation of the loading and uniformity of gadolinium in solution. Early SK-Gd operation has demonstrated high neutron-tagging efficiency, reduced backgrounds, and world-leading limits on the DSNB flux. With these advances, SK-Gd now stands at the threshold of discovering the DSNB and opens a wide range of new opportunities in astrophysics and neutrino physics.
format Preprint
id arxiv_https___arxiv_org_abs_2511_03921
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Upgrade of Super-Kamiokande with Gadolinium
Koshio, Yusuke
Nakahata, Masayuki
Sekiya, Hiroyuki
Vagins, Mark R.
Instrumentation and Detectors
High Energy Astrophysical Phenomena
Super-Kamiokande [SK] was upgraded through the addition of gadolinium sulfate to its ultrapure water, initiating the SK-Gd program. This development enables efficient neutron tagging via the large capture cross section of gadolinium, greatly improving the identification of inverse beta decay events, the primary channel for detecting the diffuse supernova neutrino background [DSNB]. The upgrade also enhances sensitivity to galactic and pre-supernova neutrinos, as well as atmospheric neutrino interactions. To realize this capability, extensive work was performed, including the construction and operation of the EGADS demonstrator, the refurbishment of the SK tank, the development of radiopure gadolinium production methods, and the validation of the loading and uniformity of gadolinium in solution. Early SK-Gd operation has demonstrated high neutron-tagging efficiency, reduced backgrounds, and world-leading limits on the DSNB flux. With these advances, SK-Gd now stands at the threshold of discovering the DSNB and opens a wide range of new opportunities in astrophysics and neutrino physics.
title Upgrade of Super-Kamiokande with Gadolinium
topic Instrumentation and Detectors
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2511.03921