Publications by Jeffrey Lidgard


Measurement of neutron-proton capture in the SNO+ water phase

Physical Review C American Physical Society (0)

A Reichold, MR Anderson, S Andringa, M Askins, S Biller, T Kroupova, E Leming, J Lidgard, I Morton-Blake, J Paton, J Tseng, E Turner, J Wang, The SNO Collaboration

The SNO+ experiment collected data as a low-threshold water Cherenkov detector from September 2017 to July 2019. Measurements of the 2.2-MeV $\gamma$ 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 $\gamma$. Analysis of the delayed coincidence between the 4.4-MeV $\gamma$ and the 2.2-MeV capture $\gamma$ 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.


Design and construction of the DEAP-3600 dark matter detector

ASTROPARTICLE PHYSICS 108 (2019) 1-23

P-A Amaudruz, M Baldwin, M Batygov, B Beltran, CE Bina, D Bishop, J Bonatt, G Boorman, MG Boulay, B Broerman, T Bromwich, JF Bueno, PM Burghardt, A Butcher, B Cai, S Chan, M Chen, R Chouinard, S Churchwell, BT Cleveland, D Cranshaw, K Dering, J DiGioseffo, S Dittmeier, FA Duncan, M Dunford, A Erlandson, N Fatemighomi, S Florian, A Flower, RJ Ford, R Gagnon, P Giampa, VV Golovko, R Gorel, R Gornea, E Grace, K Graham, DR Grant, E Gulyev, A Hall, AL Hallin, M Hamstra, PJ Harvey, C Hearns, CJ Jillings, O Kamaev, A Kemp, M Kuzniak, S Langrock, F La Zia, B Lehnert, O Li, JJ Lidgard, P Liimatainen, C Lim, T Lindner, Y Linn, S Liu, P Majewski, R Mathew, AB McDonald, T McElroy, K McFarlane, T McGinn, JB McLaughlin, S Mead, R Mehdiyev, C Mielnichuk, J Monroe, A Muir, P Nadeau, C Nantais, C Ng, AJ Noble, E O'Dwyer, C Ohlmann, K Olchanski, KS Olsen, C Ouellet, P Pasuthip, SJM Peeters, TR Pollmann, ET Rand, W Rau, C Rethmeier, F Retiere, N Seeburn, B Shaw, K Singhrao, P Skensved, B Smith, NT Smith, T Sonley, J Soukup, R Stainforth, C Stone, V Strickland, B Sur, J Tang, J Taylor, L Veloce, E Vazquez-Jauregui, J Walding, M Ward, S Westerdale, R White, E Woolsey, J Zielinski, D Collaboration


Search for invisible modes of nucleon decay in water with the SNO+ detector

Physical Review D American Physical Society 99 (2019) 032008-

M Anderson, S Andringa, E Arushanova, S Biller, L Cavalli, N Jelley, T Kroupova, E Leming, J Lidgard, I Morton-Blake, J Paton, A Reichold, J Tseng, E Turner, J-S Wang

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 deexcite, often emitting detectable gamma rays. A search for such gamma rays yields limits of 2.5×1029  y at 90% Bayesian credibility level (with a prior uniform in rate) for the partial lifetime of the neutron, and 3.6×1029  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 1.3×1028  y for nn, 2.6×1028  y for pn and 4.7×1028  y for pp, an improvement over existing limits by close to 3 orders of magnitude for the latter two.


In-situ characterization of the Hamamatsu R5912-HQE photomultiplier tubes used in the DEAP-3600 experiment

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT 922 (2019) 373-384

P-A Amaudruz, M Batygov, B Beltran, CE Bina, D Bishop, J Bonatt, G Boorman, MG Boulay, B Broerman, T Bromwich, JF Bueno, A Butcher, B Cai, S Chan, M Chen, R Chouinard, S Churchwell, BT Cleveland, D Cranshaw, K Dering, S Dittmeier, FA Duncan, M Dunford, A Erlandson, N Fatemighomi, RJ Ford, R Gagnon, P Giampa, VV Golovko, P Gorel, R Gornea, E Grace, K Graham, DR Grant, E Gulyev, A Hall, AL Hallin, M Hamstra, PJ Harvey, C Hearns, CJ Jillings, O Kamaev, A Kemp, M Kuzniak, S Langrock, F La Zia, B Lehnert, O Li, JJ Lidgard, P Liimatainen, C Lim, T Lindner, Y Linn, S Liu, R Mathew, AB McDonald, T McElroy, K McFarlane, J McLaughlin, S Mead, R Mehdiyev, C Mielnichuk, J Monroe, A Muir, P Nadeau, C Nantais, C Ng, AJ Noble, E O'Dwyer, C Ohlmann, K Olchanski, KS Olsen, C Ouellet, P Pasuthip, SJM Peeters, TR Pollmann, ET Rand, W Rau, C Rethmeier, F Retiere, N Seeburn, B Shaw, K Singhrao, P Skensved, B Smith, NJT Smith, T Sonley, R Stainforth, C Stone, V Strickland, B Sur, J Tang, J Taylor, L Veloce, E Vazquez-Jauregui, J Walding, M Ward, S Westerdale, R White, E Woolsey, J Zielinski


Search for dark matter with a 231-day exposure of liquid argon using DEAP-3600 at SNOLAB

PHYSICAL REVIEW D 100 (2019) ARTN 022004

R Ajaj, P-A Amaudruz, GR Araujo, M Baldwin, M Batygov, B Beltran, CE Bina, J Bonatt, MG Boulay, B Broerman, JF Bueno, PM Burghardt, A Butcher, B Cai, S Cavuoti, M Chen, Y Chen, BT Cleveland, D Cranshaw, K Dering, J DiGioseffo, L Doria, FA Duncan, M Dunford, A Erlandson, N Fatemighomi, G Fiorillo, S Florian, A Flower, RJ Ford, R Gagnon, D Gallacher, EA Garces, S Garg, P Giampa, D Goeldi, VV Golovko, P Gorel, K Graham, DR Grant, AL Hallin, M Hamstra, PJ Harvey, C Hearns, A Joy, CJ Jillings, O Kamaev, G Kaur, A Kemp, I Kochanek, M Kuzniak, S Langrock, F La Zia, B Lehnert, X Li, J Lidgard, T Lindner, O Litvinov, J Lock, G Longo, P Majewski, AB McDonald, T McElroy, T McGinn, JB McLaughlin, R Mehdiyev, C Mielnichuk, J Monroe, P Nadeau, C Nantais, C Ng, AJ Noble, E O'Dwyer, C Ouellet, P Pasuthip, SJM Peeters, M-C Piro, TR Pollmann, ET Rand, C Rethmeier, F Retiere, N Seeburn, K Singhrao, P Skensved, B Smith, NJT Smith, T Sonley, J Soukup, R Stainforth, C Stone, V Strickland, B Sur, J Tang, E Vazquez-Jauregui, L Veloce, S Viel, J Walding, M Waqar, M Ward, S Westerdale, J Willis, A Zuniga-Reyes, DEAP Collaboration


Measurement of the 8B solar neutrino flux in SNO+ with very low backgrounds

Physical Review D American Physical Society 99 (2019) 012012-

M Anderson, S Andringa, S Asahi, S Biller, T Kroupova, E Leming, J Lidgard, I Morton-Blake, J Paton, A Reichold, J Tseng, E Turner, J-S Wang

A measurement of the 8B solar neutrino flux has been made using a 69.2 kt-day dataset acquired with the SNO+ detector during its water commissioning phase. At energies above 6 MeV the dataset is an extremely pure sample of solar neutrino elastic scattering events, owing primarily to the detector’s deep location, allowing an accurate measurement with relatively little exposure. In that energy region the best fit background rate is 0.25+0.09−0.07  events/kt−day, significantly lower than the measured solar neutrino event rate in that energy range, which is 1.03+0.13−0.12  events/kt−day. Also using data below this threshold, down to 5 MeV, fits of the solar neutrino event direction yielded an observed flux of 2.53+0.31−0.28(stat)+0.13−0.10(syst)×106  cm−2 s−1, assuming no neutrino oscillations. This rate is consistent with matter enhanced neutrino oscillations and measurements from other experiments.


First results from the DEAP-3600 dark matter search with argon at SNOLAB

Physical Review Letters American Physical Society 121 (2018) 071801-

P-A Amaudruz, M Baldwin, B Beltran, CE Bina, D Bishop, J Bonatt, G Boorman, Boulay, B Broerman, T Bromwich, R Gagnon, P Giampa, VV Golovko, P Gorel, R Gornea, R Hakobyan, A Hall, AL Hallin, M Hamstra, PJ Harvey, M Kuźniak, S Langrock, FL Zia, B Lehnert, J Lidgard

This paper reports the first results of a direct dark matter search with the DEAP-3600 single-phase liquid argon (LAr) detector. The experiment was performed 2 km underground at SNOLAB (Sudbury, Canada) utilizing a large target mass, with the LAr target contained in a spherical acrylic vessel of 3600 kg capacity. The LAr is viewed by an array of PMTs, which would register scintillation light produced by rare nuclear recoil signals induced by dark matter particle scattering. An analysis of 4.44 live days (fiducial exposure of 9.87 tonne-days) of data taken with the nearly full detector during the initial filling phase demonstrates the detector performance and the best electronic recoil rejection using pulse-shape discrimination in argon, with leakage $<1.2\times 10^{-7}$ (90% C.L.) between 16 and 33 keV$_{ee}$. No candidate signal events are observed, which results in the leading limit on WIMP-nucleon spin-independent cross section on argon, $<1.2\times 10^{-44}$ cm$^2$ for a 100 GeV/c$^2$ WIMP mass (90% C.L.).


Scattering length monitoring at the SNO+ detector

Journal of Physics: Conference Series IOP Publishing 888 (2017) 012053-
Part of a series from Journal of Physics: Conference Series

S Langrock, J Lidgard, E Turner, L Segui, A Reichold

SNO+ is a neutrinoless double beta decay and low energy neutrino experiment located in Sudbury, Canada. To improve our understanding of the detector energy resolution and systematics, calibration systems have been developed to continuously monitor the optical properties of the detector, such as absorption, reemission and scattering. This poster provides an overview of the scattering calibration system: the Scattering Module of the Embedded LED/Laser Light Injection Entity (SMELLIE), designed to measure the scattering length in situ, over a wavelength range of 375nm - 700nm. We present analyses for both water and scintillator filled detector states.


Current status and future prospects of the SNO+ experiment

Advances in High Energy Physics Hindawi Publishing Corporation 2016 (2016) 6194250-6194250

SD Biller, LA Cavalli, JT Dunger, NA Jelley, C Jones, PG Jones, J Lidgard, K Majumdar, A Reichold, L Segui, JC-L Tseng

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$\nu\beta\beta$) 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$\nu\beta\beta$ Phase I is foreseen for 2017.


Measurement of the scintillation time spectra and pulse-shape discrimination of low-energy beta and nuclear recoils in liquid argon with DEAP-1

ArXiv (0)

P-A Amaudruz, M Batygov, B Beltran, J Bonatt, K Boudjemline, MG Boulay, B Broerman, JF Bueno, A Butcher, B Cai, T Caldwell, M Chen, R Chouinard, BT Cleveland, D Cranshaw, K Dering, F Duncan, N Fatemighomi, R Ford, R Gagnon, P Giampa, F Giuliani, M Gold, VV Golovko, P Gorel, E Grace, K Graham, DR Grant, R Hakobyan, AL Hallin, M Hamstra, P Harvey, C Hearns, J Hofgartner, CJ Jillings, M Kuźniak, I Lawson, FL Zia, O Li, JJ Lidgard, P Liimatainen, WH Lippincott, R Mathew, AB McDonald, T McElroy, K McFarlane, R Mehdiyev, DN McKinsey, J Monroe, A Muir, C Nantais, K Nicolics, J Nikkel, AJ Noble, E O'Dwyer, K Olsen, C Ouellet, P Pasuthip, SJM Peeters, T Pollmann, W Rau, F Retière, M Ronquest, N Seeburn, P Skensved, B Smith, T Sonley, J Tang, E Vázquez-Jáuregui, L Veloce, J Walding, M Ward

The DEAP-1 low-background liquid argon detector was used to measure scintillation pulse shapes of electron and nuclear recoil events and to demonstrate the feasibility of pulse-shape discrimination (PSD) down to an electron-equivalent energy of 20 keV. In the surface dataset using a triple-coincidence tag we found the fraction of beta events that are misidentified as nuclear recoils to be $<1.4\times 10^{-7}$ (90% C.L.) for energies between 43-86 keVee and for a nuclear recoil acceptance of at least 90%, with 4% systematic uncertainty on the absolute energy scale. The discrimination measurement on surface was limited by nuclear recoils induced by cosmic-ray generated neutrons. This was improved by moving the detector to the SNOLAB underground laboratory, where the reduced background rate allowed the same measurement with only a double-coincidence tag. The combined data set contains $1.23\times10^8$ events. One of those, in the underground data set, is in the nuclear-recoil region of interest. Taking into account the expected background of 0.48 events coming from random pileup, the resulting upper limit on the electronic recoil contamination is $<2.7\times10^{-8}$ (90% C.L.) between 44-89 keVee and for a nuclear recoil acceptance of at least 90%, with 6% systematic uncertainty on the absolute energy scale. We developed a general mathematical framework to describe PSD parameter distributions and used it to build an analytical model of the distributions observed in DEAP-1. Using this model, we project a misidentification fraction of approx. $10^{-10}$ for an electron-equivalent energy threshold of 15 keV for a detector with 8 PE/keVee light yield. This reduction enables a search for spin-independent scattering of WIMPs from 1000 kg of liquid argon with a WIMP-nucleon cross-section sensitivity of $10^{-46}$ cm$^2$, assuming negligible contribution from nuclear recoil backgrounds.


Improving photoelectron counting and particle identification in scintillation detectors with Bayesian techniques

ASTROPARTICLE PHYSICS 65 (2015) 40-54

M Akashi-Ronquest, P-A Amaudruz, M Batygov, B Beltran, M Bodmer, MG Boulay, B Broerman, B Buck, A Butcher, B Cai, T Caldwell, M Chen, Y Chen, B Cleveland, K Coakley, K Dering, FA Duncan, JA Formaggio, R Gagnon, D Gastler, F Giuliani, M Gold, VV Golovko, P Gorel, K Graham, E Grace, N Guerrero, V Guiseppe, AL Hallin, P Harvey, C Hearns, R Henning, A Hime, J Hofgartner, S Jaditz, CJ Jillings, C Kachulis, E Kearns, J Kelsey, JR Klein, M Kuzniak, A LaTorre, I Lawson, O Li, JJ Lidgard, P Liimatainen, S Linden, K McFarlane, DN McKinsey, S MacMullin, A Mastbaum, R Mathew, AB McDonald, D-M Mei, J Monroe, A Muir, C Nantais, K Nicolics, JA Nikkel, T Noble, E O'Dwyer, K Olsen, GDO Gann, C Ouellet, K Palladino, P Pasuthip, G Perumpilly, T Pollmann, P Rau, F Retiere, K Rielage, R Schnee, S Seibert, P Skensved, T Sonley, E Vazquez-Jauregui, L Veloce, J Walding, B Wang, J Wang, M Ward, C Zhang


Radon backgrounds in the DEAP-1 liquid-argon-based Dark Matter detector

ArXiv (0)

P-A Amaudruz, M Batygov, B Beltran, K Boudjemline, MGBBCT Caldwell, M Chen, R Chouinard, BT Cleveland, D Contreras, K Dering, F Duncan, R Ford, RGF Giuliani, MGVV Golovko, P Gorel, K Graham, DR Grant, R Hakobyan, AL Hallin, P Harvey, C Hearns, CJ Jillings, M Kuźniak, I Lawson, O Li, J Lidgard, P Liimatainen, WH Lippincott, R Mathew, AB McDonald, T McElroy, K McFarlane, D McKinsey, A Muir, C Nantais, K Nicolics, J Nikkel, T Noble, E O'Dwyer, KS Olsen, C Ouellet, P Pasuthip, T Pollmann, W Rau, F Retiere, M Ronquest, P Skensved, T Sonley, J Tang, E Vázquez-Jáuregui, L Veloce, M Ward

The DEAP-1 \SI{7}{kg} single phase liquid argon scintillation detector was operated underground at SNOLAB in order to test the techniques and measure the backgrounds inherent to single phase detection, in support of the \mbox{DEAP-3600} Dark Matter detector. Backgrounds in DEAP are controlled through material selection, construction techniques, pulse shape discrimination and event reconstruction. This report details the analysis of background events observed in three iterations of the DEAP-1 detector, and the measures taken to reduce them. The $^{222}$Rn decay rate in the liquid argon was measured to be between 16 and \SI{26}{\micro\becquerel\per\kilogram}. We found that the background spectrum near the region of interest for Dark Matter detection in the DEAP-1 detector can be described considering events from three sources: radon daughters decaying on the surface of the active volume, the expected rate of electromagnetic events misidentified as nuclear recoils due to inefficiencies in the pulse shape discrimination, and leakage of events from outside the fiducial volume due to imperfect position reconstruction. These backgrounds statistically account for all observed events, and they will be strongly reduced in the DEAP-3600 detector due to its higher light yield and simpler geometry.


Design constraints for a liquid neon detector for dark matter and solar neutrino interactions

Nuclear Physics B - Proceedings Supplements 143 (2005) 486-

MG Boulay, A Hime, J Lidgard


Measurement of IWTO-19 ash content by Near Infrared Reflectance (NIR) Analysis

Wool Technology and Sheep Breeding 52 (2004) 245-259

DJ Petrie, JJ Lidgard, JW Marler, AHM Ireland

The prediction of ash content of laboratory-scoured core samples utilising Near Infrared Reflectance Analysis (NIRA) has been investigated. Modified Partial Least Squares (MPLS) Regression was found to underestimate ash content when the sample being tested contained significant quantities of dag. The underestimation was not a consequence of saturation of the NIRA detector but rather appeared to be due to an inability of the MPLS technique to adequately account for dag which was present in the sample but masked by wool. Application of Artificial Neu ral Networks (ANN) Regression to the calibration data set produced improved results. The underestimation at higher ash levels was not as evident, indicating that ANN is better able to utilise the spectral information to predict total ash content. High levels of dag were found to adversely affect the repeatability of the IWTO-19 method for determining ash content. Uneven distribution of dag within samples was believed to be responsible. This finding has implications for NIRA, as any method of prediction can only be as good as the reference method to which it is calibrated.


Commissioning of ELLIE for SNO+

ArXiv (0)

E Falk, J Lidgard, MI Stringer, E Turner

SNO+ is a neutrinoless double beta decay and low energy neutrino experiment located in Sudbury, Canada. To improve our understanding of the detector energy resolution and systematics, calibration systems have been developed to continuously monitor the optical properties of the detector, such as: absorption, re-emission, scattering and timing. A part of this in-situ optical calibration system is the Embedded LED/Laser Light Injection Entity (ELLIE). It consists of three subsystems: AMELLIE, SMELLIE, TELLIE. The attenuation module (AMELLIE) is designed to monitor the total optical attenuation, whereas the optical scattering over a wavelength range of 375nm -- 700nm will be characterized by the scattering module (SMELLIE). The timing module (TELLIE) aims to measure the timing characteristics of the photomultiplier tubes. We present the planned commissioning of these three systems, the running of which began early 2017.


Design Constraints for a WIMP Dark Matter and pp Solar Neutrino Liquid Neon Scintillation Detector

ArXiv (0)

MG Boulay, A Hime, J Lidgard

Detailed Monte-Carlo simulations were used to evaluate the performance of a liquid neon scintillation detector for dark matter and low-energy solar neutrino interactions. A maximum-likelihood event vertex fitter including PMT time information was developed, which significantly improves position resolution over spatial-only algorithms, and substantially decreases the required detector size and achievable analysis energy threshold. The ultimate sensitivity to WIMP dark matter and the pp flux uncertainty are evaluated as a function of detector size. The dependence on the neon scintillation and PMT properties are evaluated. A 300 cm radius detector would allow a ~13 keV threshold, a pp flux uncertainty of ~1%, and limits on the spin-independent WIMP-nucleon cross-section of ~10^{-46} cm^2 for a 100 GeV WIMP, using commercially available PMTs. Detector response calibration and background requirements for a precision pp measurement are defined. Internal radioactivity requirements for uranium, thorium, and krypton are specified, and it is shown that the PMT data could be used for an in-situ calibration of the troublesome krypton-85. A set of measurements of neon scintillation properties and PMT characteristics are outlined which will be needed in order to evaluate feasibility and fully optimize the design of a neon-based detector.