16N as a calibration source for Super-Kamiokande

Blaufuss, E.; Guillian, G.; Fukuda, Y.; Fukuda, Seisuke; Ishitsuka, M.; Itow, Y.; Kajita, T.; Kameda, J.; Kaneyuki, K.; Kobayashi, Kazuyoshi; Kobayashi, Yoshiyuki; Koshio, Y.; Miura, Makoto; Moriyama, S.; Nakahata, M.; Nakayama, S.; Obayashi, Y.; Okada, Atsushi; Okumura, K.; Sakurai, N.; Shiozawa, M.; Suzuki, Y.; Takeuchi, Hideki; Takeuchi, Y.; Toshito, T.; Totsuka, Y.; Yamada, Shoichi; Earl, M.; Habig, A.; Kearns, E.; Messier, M. D.; Scholberg, K.; Stone, J. L.; Sulak, L.; Walter, C. W.; Goldhaber, M.; Barszczak, T.; Casper, D.; Gajewski, W.; Kropp, W. R.; Mine, S.; Price, L. R.; Smy, M. B.; Sobel, H. W.; Vagins, M. R.; Ganezer, K. S.; Keig, W. E.; Ellsworth, R. W.; Tasaka, S.; Kibayashi, A.; Learned, J. G.; Matsuno, S.; Takemori, D.; Hayato, Y.; Ishii, T.; Kobayashi, T.; Nakamura, K.; Oyama, Y.; Sakai, Akito; Sakuda, M.; Sasaki, O.; Echigo, S.; Kohama, M.; Suzuki, A.; Inagaki, T.; Nishikawa, K.; Haines, T. J.; Kim, B. K.; Sanford, R.; Svoboda, R.; Chen, M. L.; Goodman, J. A.; Sullivan, G. W.; Hill, J.; Jung, C. K.; Martens, K.; Malek, M.; Mauger, C.; McGrew, C.; Sharkey, E.; Viren, B.; Yanagisawa, C.; Kirisawa, Makoto; Inaba, S.; Mitsuda, C.; Miyano, K.; Okazawa, H.; Saji, C.; Takahashi, Miho; Takahata, M.; Nagashima, Y.; Nitta, K.; Takita, M.; Yoshida, Masato; Kim, S. B.; Etoh, M.; Gando, Y.; Hasegawa, T.; Inoue, K.

doi:10.1016/s0168-9002(00)00900-1

Cited by 39 publications

(14 citation statements)

References 20 publications

(26 reference statements)

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“…At the Kamioka depth the expected rate of stopping muons is about 365/kton day (this is consistent with the Super-Kamiokande measurement of 220/kton day, after taking into account the detection efficiency of 0.65 [18]). Only negative muons can undergo nuclear capture, and the fraction of negative muons is 44% [18]. The fraction of negative muons undergoing capture on 12 C in hydrocarbons is 7.7% [19,20].…”

Section: Muon Production Of Secondariessupporting

confidence: 86%

Measuring the cosmic ray muon-induced fast neutron spectrum by (n,p) isotope production reactions in underground detectors

Galbiati

Beacom

2005

Phys. Rev. C

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While cosmic ray muons themselves are relatively easy to veto in underground detectors, their interactions with nuclei create more insidious backgrounds via: (i) the decays of long-lived isotopes produced by muon-induced spallation reactions inside the detector, (ii) spallation reactions initiated by fast muon-induced neutrons entering from outside the detector, and (iii) nuclear recoils initiated by fast muon-induced neutrons entering from outside the detector. These backgrounds, which are difficult to veto or shield against, are very important for solar, reactor, dark matter, and other underground experiments, especially as increased sensitivity is pursued. We used fluka to calculate the production rates and spectra of all prominent secondaries produced by cosmic ray muons, in particular focusing on secondary neutrons, due to their importance. Since the neutron spectrum is steeply falling, the total neutron production rate is sensitive just to the relatively soft neutrons, and not to the fast-neutron component. We show that the neutron spectrum in the range ∼ 10-100 MeV can instead be probed by the (n, p)-induced isotope production rates 12 C(n, p) 12 B and 16 O(n, p) 16 N in oil-and water-based detectors. The result for 12 B is in good agreement with the recent KamLAND measurement. Besides testing the calculation of muon secondaries, these results are also of practical importance, since 12 B (T 1/2 = 20.2 ms, Q = 13.4 MeV) and 16 N (T 1/2 = 7.13 s, Q = 10.4 MeV) are among the dominant spallation backgrounds in these detectors. PACS numbers: 25.30.Mr, 25.40.Sc, 96.40.Tv

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Section: Muon Production Of Secondariessupporting

confidence: 86%

Measuring the cosmic ray muon-induced fast neutron spectrum by (n,p) isotope production reactions in underground detectors

Galbiati

Beacom

2005

Phys. Rev. C

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“…The Super-K 16 N calibration study reports that the production rate of 16 N by stopping muons is 11 per day in an 11.5 kton volume [57]. The rate from our calculation is 3 × 10 −7 µ −1 g −1 cm 2 .…”

Section: B Comparison To Super-k Measurementsmentioning

confidence: 57%

“…Of unstable isotopes with high yields, 16 N is cut the least. For 16 N decay, 66% of the time there is a 6.1 MeV gamma ray, which leads to an electron-equivalent energy reduced by a factor ∼ 1/4 [57]. As a result, the beta spectrum is shifted to higher energies, making it unaffected by the 3.5 MeV cut.…”

Section: Isotope and Neutron Production And Distributionsmentioning

confidence: 99%

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First calculation of cosmic-ray muon spallation backgrounds for MeV astrophysical neutrino signals in Super-Kamiokande

Beacom

2014

Phys. Rev. C

104

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When muons travel through matter, their energy losses lead to nuclear breakup ("spallation") processes. The delayed decays of unstable daughter nuclei produced by cosmic-ray muons are important backgrounds for low-energy astrophysical neutrino experiments, e.g., those seeking to detect solar neutrino or diffuse supernova neutrino background (DSNB) signals. Even though Super-Kamiokande has strong general cuts to reduce these spallation-induced backgrounds, the remaining rate before additional cuts for specific signals is much larger than the signal rates for kinetic energies of about 6 -18 MeV. Surprisingly, there is no published calculation of the production and properties of these backgrounds in water, though there are such studies for scintillator. Using the simulation code FLUKA and theoretical insights, we detail how muons lose energy in water, produce secondary particles, how and where these secondaries produce isotopes, and the properties of the backgrounds from their decays. We reproduce Super-Kamiokande measurements of the total background to within a factor of 2, which is good given that the isotope yields vary by orders of magnitude and that some details of the experiment are unknown to us at this level. Our results break aggregate data into component isotopes, reveal their separate production mechanisms, and preserve correlations between them. We outline how to implement more effective background rejection techniques using this information. Reducing backgrounds in solar and DSNB studies by even a factor of a few could help lead to important new discoveries.

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“…Various calibrations are used to evaluate the performance of the reconstruction as detailed in Refs. [54,55]. This analysis considers five event categories, neutrino NCQE interactions ("ν-NCQE"), antineutrino NCQE interactions ("ν-NCQE"), all other NC interactions ("NCother"), CC interactions, and accidental (beam-unrelated) backgrounds.…”

Section: Reconstruction and Selectionmentioning

confidence: 99%

Measurement of neutrino and antineutrino neutral-current quasielasticlike interactions on oxygen by detecting nuclear deexcitation γ rays

Abe¹,

Akutsu²,

Ali³

et al. 2019

Phys. Rev. D

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Neutrino-and antineutrino-oxygen neutral-current quasielasticlike interactions are measured at Super-Kamiokande using nuclear deexcitation γ rays to identify signal-like interactions in data from a 14.94ð16.35Þ × 10 20 protons-on-target exposure of the T2K neutrino (antineutrino) beam. The measured flux-averaged cross sections on oxygen nuclei are hσ ν-NCQE i ¼ 1.70 AE 0.17ðstat:Þ þ0.51 −0.38 ðsyst:Þ × 10 −38 cm 2 =oxygen with a fluxaveraged energy of 0.82 GeV and hσ¯ν -NCQE i ¼ 0.98 AE 0.16ðstat:Þ þ0.26 −0.19 ðsyst:Þ × 10 −38 cm 2 =oxygen with a flux-averaged energy of 0.68 GeV, for neutrinos and antineutrinos, respectively. These results are the most precise to date, and the antineutrino result is the first cross section measurement of this channel. They are compared with various theoretical predictions. The impact on evaluation of backgrounds to searches for supernova relic neutrinos at present and future water Cherenkov detectors is also discussed.

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16N as a calibration source for Super-Kamiokande

Cited by 39 publications

References 20 publications

Measuring the cosmic ray muon-induced fast neutron spectrum by (n,p) isotope production reactions in underground detectors

Measuring the cosmic ray muon-induced fast neutron spectrum by (n,p) isotope production reactions in underground detectors

First calculation of cosmic-ray muon spallation backgrounds for MeV astrophysical neutrino signals in Super-Kamiokande

Measurement of neutrino and antineutrino neutral-current quasielasticlike interactions on oxygen by detecting nuclear deexcitation γ rays

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