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Antibacterial Activity of Zinc Oxide Thin Films by Atomic Layer Deposition for Personal Protective Equipment Applications
Authors:
Li Tao,
Kinga Vojnits,
Man In Lam,
Xuejun Lu,
Sepideh Pakpour,
Jian Liu
Abstract:
The global pandemic has significantly increased the demand for personal protective equipment (PPE). The antimicrobial coating has been broadly applied to PPE to improve its prevention capability, especially after prolonged usage. However, antimicrobial coating by traditional methods, such as chemical vapor deposition, spraying, and slurry coating, suffers from drawbacks such as low efficiency, poo…
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The global pandemic has significantly increased the demand for personal protective equipment (PPE). The antimicrobial coating has been broadly applied to PPE to improve its prevention capability, especially after prolonged usage. However, antimicrobial coating by traditional methods, such as chemical vapor deposition, spraying, and slurry coating, suffers from drawbacks such as low efficiency, poor coverage, and loose adhesion to PPE. To overcome these limitations, this work adopted an atomic layer deposition (ALD) technique to deposit a zinc oxide (ZnO) thin film (~ 312.8 nm thick) as an antimicrobial coating and proved its advantage for depositing uniform ZnO coating on PPE with a fabric structure. Analysis by X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the crystal structure and chemical composition of the ALD-ZnO. Ultraviolet-visible spectra disclosed a high absorption level of about 4.8 from 200 nm to 380 nm wavelength for ALD-ZnO, in contrast to 3.8 for commercial ZnO powders. Moreover, the ALD-ZnO exhibited strong antimicrobial properties when tested against Escherichia coli (E.Coli) in contrast to the control and bare glass samples. The colony-forming unit (CFU/ml) remained zero for all ALD-ZnO samples while varying between 2.30*109 and 4.97*109 with a median of 4.36*109 for the control and between 9.10*108 and 3.27*109 with a median of 2.04x 109 for the bare glass. Statistic analysis using null-hypothesis significance testing revealed that the calculated P value, between bare glass and control, ALD-ZnO and control, and bare glass and control, were all smaller than 0.0001 and significantly smaller than 0.05 alpha value, suggesting a high confidence level of ALD-ZnO as the main factor for preventing E.Coli growth.
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Submitted 3 February, 2023;
originally announced February 2023.
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A Method to Load Tellurium in Liquid Scintillator for the Study of Neutrinoless Double Beta Decay
Authors:
D. J. Auty,
D. Bartlett,
S. D. Biller,
D. Chauhan,
M. Chen,
O. Chkvorets,
S. Connolly,
X. Dai,
E. Fletcher,
K. Frankiewicz,
D. Gooding,
C. Grant,
S. Hall,
D. Horne,
S. Hans,
B. Hreljac,
T. Kaptanoglu,
B. Krar,
C. Kraus,
T. Kroupova',
I. Lam,
Y. Liu,
S. Maguire,
C. Miller,
S. Manecki
, et al. (12 additional authors not shown)
Abstract:
A method has been developed to load tellurium into liquid scintillator so as to permit searches for neutrinoless double beta decay with high sensitivity. The approach involves the synthesis of an oil-soluble tellurium compound from telluric acid and an organic diol. The process utilises distillable chemicals that can be safely handled underground and affords low radioactive backgrounds, low optica…
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A method has been developed to load tellurium into liquid scintillator so as to permit searches for neutrinoless double beta decay with high sensitivity. The approach involves the synthesis of an oil-soluble tellurium compound from telluric acid and an organic diol. The process utilises distillable chemicals that can be safely handled underground and affords low radioactive backgrounds, low optical absorption and high light yields at loading levels of at least several percent Te by weight.
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Submitted 4 April, 2023; v1 submitted 23 December, 2022;
originally announced December 2022.
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Optical calibration of the SNO+ detector in the water phase with deployed sources
Authors:
SNO+ Collaboration,
:,
M. R. Anderson,
S. Andringa,
M. Askins,
D. J. Auty,
F. Barão,
N. Barros,
R. Bayes,
E. W. Beier,
A. Bialek,
S. D. Biller,
E. Blucher,
M. Boulay,
E. Caden,
E. J. Callaghan,
J. Caravaca,
M. Chen,
O. Chkvorets,
B. Cleveland,
D. Cookman,
J. Corning,
M. A. Cox,
C. Deluce,
M. M. Depatie
, et al. (98 additional authors not shown)
Abstract:
SNO+ is a large-scale liquid scintillator experiment with the primary goal of searching for neutrinoless double beta decay, and is located approximately 2 km underground in SNOLAB, Sudbury, Canada. The detector acquired data for two years as a pure water Cherenkov detector, starting in May 2017. During this period, the optical properties of the detector were measured in situ using a deployed light…
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SNO+ is a large-scale liquid scintillator experiment with the primary goal of searching for neutrinoless double beta decay, and is located approximately 2 km underground in SNOLAB, Sudbury, Canada. The detector acquired data for two years as a pure water Cherenkov detector, starting in May 2017. During this period, the optical properties of the detector were measured in situ using a deployed light diffusing sphere, with the goal of improving the detector model and the energy response systematic uncertainties. The measured parameters included the water attenuation coefficients, effective attenuation coefficients for the acrylic vessel, and the angular response of the photomultiplier tubes and their surrounding light concentrators, all across different wavelengths. The calibrated detector model was validated using a deployed tagged gamma source, which showed a 0.6% variation in energy scale across the primary target volume.
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Submitted 4 October, 2021; v1 submitted 7 June, 2021;
originally announced June 2021.
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The SNO+ Experiment
Authors:
SNO+ Collaboration,
:,
V. Albanese,
R. Alves,
M. R. Anderson,
S. Andringa,
L. Anselmo,
E. Arushanova,
S. Asahi,
M. Askins,
D. J. Auty,
A. R. Back,
S. Back,
F. Barão,
Z. Barnard,
A. Barr,
N. Barros,
D. Bartlett,
R. Bayes,
C. Beaudoin,
E. W. Beier,
G. Berardi,
A. Bialek,
S. D. Biller,
E. Blucher
, et al. (229 additional authors not shown)
Abstract:
The SNO+ experiment is located 2 km underground at SNOLAB in Sudbury, Canada. A low background search for neutrinoless double beta ($0νββ$) decay will be conducted using 780 tonnes of liquid scintillator loaded with 3.9 tonnes of natural tellurium, corresponding to 1.3 tonnes of $^{130}$Te. This paper provides a general overview of the SNO+ experiment, including detector design, construction of pr…
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The SNO+ experiment is located 2 km underground at SNOLAB in Sudbury, Canada. A low background search for neutrinoless double beta ($0νββ$) decay will be conducted using 780 tonnes of liquid scintillator loaded with 3.9 tonnes of natural tellurium, corresponding to 1.3 tonnes of $^{130}$Te. This paper provides a general overview of the SNO+ experiment, including detector design, construction of process plants, commissioning efforts, electronics upgrades, data acquisition systems, and calibration techniques. The SNO+ collaboration is reusing the acrylic vessel, PMT array, and electronics of the SNO detector, having made a number of experimental upgrades and essential adaptations for use with the liquid scintillator. With low backgrounds and a low energy threshold, the SNO+ collaboration will also pursue a rich physics program beyond the search for $0νββ$ decay, including studies of geo- and reactor antineutrinos, supernova and solar neutrinos, and exotic physics such as the search for invisible nucleon decay. The SNO+ approach to the search for $0νββ$ decay is scalable: a future phase with high $^{130}$Te-loading is envisioned to probe an effective Majorana mass in the inverted mass ordering region.
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Submitted 25 August, 2021; v1 submitted 23 April, 2021;
originally announced April 2021.
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Development, characterisation, and deployment of the SNO+ liquid scintillator
Authors:
SNO+ Collaboration,
:,
M. R. Anderson,
S. Andringa,
L. Anselmo,
E. Arushanova,
S. Asahi,
M. Askins,
D. J. Auty,
A. R. Back,
Z. Barnard,
N. Barros,
D. Bartlett,
F. Barão,
R. Bayes,
E. W. Beier,
A. Bialek,
S. D. Biller,
E. Blucher,
R. Bonventre,
M. Boulay,
D. Braid,
E. Caden,
E. J. Callaghan,
J. Caravaca
, et al. (201 additional authors not shown)
Abstract:
A liquid scintillator consisting of linear alkylbenzene as the solvent and 2,5-diphenyloxazole as the fluor was developed for the SNO+ experiment. This mixture was chosen as it is compatible with acrylic and has a competitive light yield to pre-existing liquid scintillators while conferring other advantages including longer attenuation lengths, superior safety characteristics, chemical simplicity,…
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A liquid scintillator consisting of linear alkylbenzene as the solvent and 2,5-diphenyloxazole as the fluor was developed for the SNO+ experiment. This mixture was chosen as it is compatible with acrylic and has a competitive light yield to pre-existing liquid scintillators while conferring other advantages including longer attenuation lengths, superior safety characteristics, chemical simplicity, ease of handling, and logistical availability. Its properties have been extensively characterized and are presented here. This liquid scintillator is now used in several neutrino physics experiments in addition to SNO+.
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Submitted 21 February, 2021; v1 submitted 25 November, 2020;
originally announced November 2020.
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Measurement of neutron-proton capture in the SNO+ water phase
Authors:
The SNO+ Collaboration,
:,
M. R. Anderson,
S. Andringa,
M. Askins,
D. J. Auty,
N. Barros,
F. Barão,
R. Bayes,
E. W. Beier,
A. Bialek,
S. D. Biller,
E. Blucher,
R. Bonventre,
M. Boulay,
E. Caden,
E. J. Callaghan,
J. Caravaca,
D. Chauhan,
M. Chen,
O. Chkvorets,
B. Cleveland,
M. A. Cox,
M. M. Depatie,
J. Dittmer
, et al. (108 additional authors not shown)
Abstract:
The SNO+ experiment collected data as a low-threshold water Cherenkov detector from September 2017 to July 2019. Measurements of the 2.2-MeV $γ$ produced by neutron capture on hydrogen have been made using an Am-Be calibration source, for which a large fraction of emitted neutrons are produced simultaneously with a 4.4-MeV $γ$. Analysis of the delayed coincidence between the 4.4-MeV $γ$ and the 2.…
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The SNO+ experiment collected data as a low-threshold water Cherenkov detector from September 2017 to July 2019. Measurements of the 2.2-MeV $γ$ produced by neutron capture on hydrogen have been made using an Am-Be calibration source, for which a large fraction of emitted neutrons are produced simultaneously with a 4.4-MeV $γ$. Analysis of the delayed coincidence between the 4.4-MeV $γ$ and the 2.2-MeV capture $γ$ revealed a neutron detection efficiency that is centered around 50% and varies at the level of 1% across the inner region of the detector, which to our knowledge is the highest efficiency achieved among pure water Cherenkov detectors. In addition, the neutron capture time constant was measured and converted to a thermal neutron-proton capture cross section of $336.3^{+1.2}_{-1.5}$ mb.
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Submitted 13 July, 2020; v1 submitted 24 February, 2020;
originally announced February 2020.
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Search for invisible modes of nucleon decay in water with the SNO+ detector
Authors:
SNO+ Collaboration,
:,
M. Anderson,
S. Andringa,
E. Arushanova,
S. Asahi,
M. Askins,
D. J. Auty,
A. R. Back,
Z. Barnard,
N. Barros,
D. Bartlett,
F. Barão,
R. Bayes,
E. W. Beier,
A. Bialek,
S. D. Biller,
E. Blucher,
R. Bonventre,
M. Boulay,
D. Braid,
E. Caden,
E. J. Callaghan,
J. Caravaca,
J. Carvalho
, et al. (173 additional authors not shown)
Abstract:
This paper reports results from a search for nucleon decay through 'invisible' modes, where no visible energy is directly deposited during the decay itself, during the initial water phase of SNO+. However, such decays within the oxygen nucleus would produce an excited daughter that would subsequently de-excite, often emitting detectable gamma rays. A search for such gamma rays yields limits of…
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This paper reports results from a search for nucleon decay through 'invisible' modes, where no visible energy is directly deposited during the decay itself, during the initial water phase of SNO+. However, such decays within the oxygen nucleus would produce an excited daughter that would subsequently de-excite, often emitting detectable gamma rays. A search for such gamma rays yields limits of $2.5 \times 10^{29}$ y at 90% Bayesian credibility level (with a prior uniform in rate) for the partial lifetime of the neutron, and $3.6 \times 10^{29}$ y for the partial lifetime of the proton, the latter a 70% improvement on the previous limit from SNO. We also present partial lifetime limits for invisible dinucleon modes of $1.3\times 10^{28}$ y for $nn$, $2.6\times 10^{28}$ y for $pn$ and $4.7\times 10^{28}$ y for $pp$, an improvement over existing limits by close to three orders of magnitude for the latter two.
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Submitted 13 December, 2018;
originally announced December 2018.
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Internal Backgrounds in the Water Phase of SNO+
Authors:
Ian Lam
Abstract:
SNO+ is a neutrinoless double-beta decay ($0νββ$) search experiment using 780 tonnes of tellurium-loaded liquid scintillator. The experiment is currently collecting data in the first of three planned phases, in which the detector is filled with ultrapure water. During this phase, the cleanliness of the water can be assayed using in situ measurements of $^{214}$Bi and $^{208}$Tl (daughter nuclei of…
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SNO+ is a neutrinoless double-beta decay ($0νββ$) search experiment using 780 tonnes of tellurium-loaded liquid scintillator. The experiment is currently collecting data in the first of three planned phases, in which the detector is filled with ultrapure water. During this phase, the cleanliness of the water can be assayed using in situ measurements of $^{214}$Bi and $^{208}$Tl (daughter nuclei of $^{238}$U and $^{232}$Th, respectively). These results will both inform preparation for scintillator fill and support water phase physics analyses like the search for invisible nucleon decay modes.
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Submitted 28 August, 2018;
originally announced August 2018.
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Current Status and Future Prospects of the SNO+ Experiment
Authors:
SNO+ Collaboration,
:,
S. Andringa,
E. Arushanova,
S. Asahi,
M. Askins,
D. J. Auty,
A. R. Back,
Z. Barnard,
N. Barros,
E. W. Beier,
A. Bialek,
S. D. Biller,
E. Blucher,
R. Bonventre,
D. Braid,
E. Caden,
E. Callaghan,
J. Caravaca,
J. Carvalho,
L. Cavalli,
D. Chauhan,
M. Chen,
O. Chkvorets,
K. Clark
, et al. (133 additional authors not shown)
Abstract:
SNO+ is a large liquid scintillator-based experiment located 2km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta de…
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SNO+ is a large liquid scintillator-based experiment located 2km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta decay (0$νββ$) of 130Te. In Phase I, the detector will be loaded with 0.3% natural tellurium, corresponding to nearly 800 kg of 130Te, with an expected effective Majorana neutrino mass sensitivity in the region of 55-133 meV, just above the inverted mass hierarchy. Recently, the possibility of deploying up to ten times more natural tellurium has been investigated, which would enable SNO+ to achieve sensitivity deep into the parameter space for the inverted neutrino mass hierarchy in the future. Additionally, SNO+ aims to measure reactor antineutrino oscillations, low-energy solar neutrinos, and geoneutrinos, to be sensitive to supernova neutrinos, and to search for exotic physics. A first phase with the detector filled with water will begin soon, with the scintillator phase expected to start after a few months of water data taking. The 0$νββ$ Phase I is foreseen for 2017.
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Submitted 28 January, 2016; v1 submitted 24 August, 2015;
originally announced August 2015.