Nigel James Telfer Smith

• Doctor of Philosophy
• Executive Director and CEO at TRIUMF

The specific activity of the $$\beta $$ β decay of $$^{39}$$ 39 Ar in atmospheric argon is measured using the DEAP-3600 detector. DEAP-3600, located 2 km underground at SNOLAB, uses a total of (3269 ± 24) kg of liquid argon distilled from the atmosphere to search for dark matter. This detector is well-suited to measure the decay of $$^{39}$$ 39 Ar...

The specific activity of the beta decay of $^{39}$Ar in atmospheric argon is measured using the DEAP-3600 detector. DEAP-3600, located 2 km underground at SNOLAB, uses a total of (3269 $\pm$ 24) kg of liquid argon distilled from the atmosphere to search for dark matter. This detector with very low background uses pulseshape discrimination to differ...

This review demonstrates the unique role of the neutrino by discussing in detail the physics of and with neutrinos. We deal with neutrino sources, neutrino oscillations, absolute masses, interactions, the possible existence of sterile neutrinos, and theoretical implications. In addition, synergies of neutrino physics with other research fields are...

DOI:https://doi.org/10.1103/PhysRevD.105.029901

Dark matter with Planck-scale mass (≃1019 GeV/c2) arises in well-motivated theories and could be produced by several cosmological mechanisms. A search for multiscatter signals from supermassive dark matter was performed with a blind analysis of data collected over a 813 d live time with DEAP-3600, a 3.3 t single-phase liquid argon-based detector at...

This review demonstrates the unique role of the neutrino by discussing in detail the physics of and with neutrinos. We deal with neutrino sources, neutrino oscillations, absolute masses, interactions, the possible existence of sterile neutrinos, and theoretical implications. In addition, synergies of neutrino physics with other research fields are...

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from $$^{39}\text{ Ar }$$ 39 Ar beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction...

Dark matter particles with Planck-scale mass ($\simeq10^{19}\text{GeV}/c^2$) arise in well-motivated theories and could be produced by several cosmological mechanisms. Using a blind analysis of data collected over a 813 d live time with DEAP-3600, a 3.3 t single-phase liquid argon-based dark matter experiment at SNOLAB, a search for supermassive da...

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from $^{39}$Ar beta decays and is suppressed using pulseshape discrimination (PSD). We use two types of PSD algorithm: the prompt-fraction, which considers the fraction of the scintillat...

This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive...

DEAP-3600 is a single-phase liquid argon detector aiming to directly detect weakly interacting massive particles (WIMPs), located at SNOLAB (Sudbury, Canada). After analyzing data taken during the first year of operation, a null result was used to place an upper bound on the WIMP-nucleon, spin-independent, isoscalar cross section. This study reinte...

DEAP-3600 is a single-phase liquid argon detector aiming to directly detect Weakly Interacting Massive Particles (WIMPs), located at SNOLAB (Sudbury, Canada). After analyzing data taken during the first year of operation, a null result was used to place an upper bound on the WIMP-nucleon spin-independent, isoscalar cross section. This study reinter...

DEAP-3600 is a liquid-argon scintillation detector looking for dark matter. Scintillation events in the liquid argon (LAr) are registered by 255 photomultiplier tubes (PMTs), and pulseshape discrimination (PSD) is used to suppress electromagnetic background events. The excellent PSD performance of LAr makes it a viable target for dark matter search...

DEAP-3600 is a liquid-argon scintillation detector looking for dark matter. Scintillation events in the liquid argon (LAr) are registered by 255 photomultiplier tubes (PMTs), and pulseshape discrimination (PSD) is used to suppress electromagnetic background events. The excellent PSD performance of LAr makes it a viable target for dark matter search...

The DEAP-3600 experiment is searching for weakly interacting massive particles dark matter with a 3.3 ×103kg single phase liquid argon (LAr) target, located 2.1 km underground at SNOLAB. The experimental signature of dark matter interactions is kilo electron volt–scale Ar40 nuclear recoils producing 128 nm LAr scintillation photons observed by phot...

DEAP-3600 is a single-phase liquid argon (LAr) direct-detection dark matter experiment, operating 2 km underground at SNOLAB (Sudbury, Canada). The detector consists of 3279 kg of LAr contained in a spherical acrylic vessel. This paper reports on the analysis of a 758 tonne·day exposure taken over a period of 231 live-days during the first year of...

The DEAP-3600 experiment is searching for WIMP dark matter with a 3.3 tonne single phase liquid argon (LAr) target, located 2.1 km underground at SNOLAB. The experimental signature of dark matter interactions is keV-scale $^{40}$Ar nuclear recoils (NR) producing 128 nm LAr scintillation photons observed by PMTs. The largest backgrounds in DEAP-3600...

DEAP-3600 is a single-phase liquid argon (LAr) direct-detection dark matter experiment, operating 2 km underground at SNOLAB (Sudbury, Canada). The detector consists of 3279 kg of LAr contained in a spherical acrylic vessel. This paper reports on the analysis of a 758 tonne\cdot day exposure taken over a period of 231 live-days during the first yea...

The Hamamatsu R5912-HQE photomultiplier-tube (PMT) is a novel high-quantum efficiency PMT. It is currently used in the DEAP-3600 dark matter detector and is of significant interest for future dark matter and neutrino experiments where high signal yields are needed. We report on the methods developed for in-situ characterization and monitoring of DE...

This Letter 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 P...

The Dark matter Experiment using Argon Pulse-shape discrimination (DEAP) has been designed for a direct detection search for particle dark matter using a single-phase liquid argon target. The projected cross section sensitivity for DEAP-3600 to the spin-independent scattering of Weakly Interacting Massive Particles (WIMPs) on nucleons is $10^{-46}~...

The Dark matter Experiment using Argon Pulse-shape discrimination (DEAP) has been designed for a direct detection search for particle dark matter using a single-phase liquid argon target. The projected cross section sensitivity for DEAP-3600 to the spin-independent scattering of Weakly Interacting Massive Particles (WIMPs) on nucleons is $10^{-46}~...

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 PM...

We present results from the measurement of the neutron production rate in lead by high energy cosmic-ray muons at a depth of 2850 m water equivalent (mean muon energy of 260 GeV). A tonne-scale highly segmented plastic scintillator detector was utilised to detect both the energy depositions from the traversing muons as well as the delayed radiative...

A measurement is presented of the neutron production rate in lead by high energy cosmic-ray muons at a depth of 2850 m water equivalent (w.e.) and a mean muon energy of 260 GeV. The measurement exploits the delayed coincidences between muons and the radiative capture of induced neutrons in a highly segmented tonne scale plastic scintillator detecto...

This laboratory portrait describes the developing infrastructure and science program at the Canadian deep underground research facility, SNOLAB. Several contemporary science studies in particle and astro-particle physics, such as Galactic dark matter searches, man-made, terrestrial, solar and supernova neutrino, and neutrino-less double-beta studie...

Several of the major questions studied in contemporary astro-particle and sub-atomic physics are performed through weak interaction studies or rare event searches that require the ultra-quiet environment afforded by deep underground facilities, where the cosmic radiation induced backgrounds in the detection systems are reduced to a manageable level...

The rigorous radiation background constraints imposed by several studies in particle and astro-particle physics, such as Galactic dark-matter searches, man-made, terrestrial, solar and supernova neutrino studies and 0νββ-decay studies, require deep underground science facilities to afford shielding from penetrating cosmic rays and their secondary b...

Deep underground science facilities provide access to the low radiation environment required to undertake several strands of particle physics and astro-particle physics experiments, such as Galactic dark matter searches, man-made, terrestrial, solar and supernova neutrino studies and 0νββ-decay studies. In addition, new threads of research focused...

The rigorous radiation background constraints imposed by several studies in particle and astro-particle physics, such as Galactic dark matter searches, man-made, terrestrial, solar and supernova neutrino studies and 0νββ-decay studies, require deep underground science facilities to afford shielding from penetrating cosmic rays and their secondary b...

We report the activity measured in rainwater samples collected in the Greater Sudbury area of eastern Canada on 3, 16, 20, and 26 April 2011. The samples were γ-ray counted in a germanium detector and the isotopes ¹³¹I and ¹³⁷Cs, produced by the fission of ²³⁵U, and ¹³⁴Cs, produced by neutron capture on ¹³³Cs, were observed at elevated levels compa...

We studied the application of statistical reconstruction algorithms, namely maximum likelihood and least squares methods, to the problem of event reconstruction in a dual phase liquid xenon detector. An iterative method was developed for in-situ reconstruction of the PMT light response functions from calibration data taken with an uncollimated γ-ra...

We studied the application of statistical reconstruction algorithms, namely maximum likelihood and least squares methods, to the problem of event reconstruction in a dual phase liquid xenon detector. An iterative method was developed for in-situ reconstruction of the PMT light response functions from calibration data taken with an uncollimated gamm...

ZEPLIN-III is a two-phase xenon direct dark matter experiment located at the Boulby Mine (UK). After its first science run in 2008 it was upgraded with: an array of low background photomultipliers, a new anti-coincidence detector system with plastic scintillator and an improved calibration system. After 319 days of data taking the second science ru...

Plastic scintillators are widely used in industry, medicine and scientific research, including nuclear and particle physics. Although one of their most common applications is in neutron detection, experimental data on their response to low-energy nuclear recoils are scarce. Here, the relative scintillation efficiency for neutron-induced nuclear rec...

We report experimental upper limits on WIMP-nucleon elastic scattering cross sections from the second science run of ZEPLIN-III at the Boulby Underground Laboratory. A raw fiducial exposure of 1,344 kg.days was accrued over 319 days of continuous operation between June 2010 and May 2011. A total of eight events was observed in the signal acceptance...

We present an experimental study of single electron emission in ZEPLIN-III, a two-phase xenon experiment built to search for dark matter WIMPs, and discuss applications enabled by the excellent signal-to-noise ratio achieved in detecting this signature. Firstly, we demonstrate a practical method for precise measurement of the free electron lifetime...

ZE3RA is the software package responsible for processing the raw data from the ZEPLIN-III dark matter experiment and its reduction into a set of parameters used in all subsequent analyses. The detector is a liquid xenon time projection chamber with scintillation and electroluminescence signals read out by an array of 31 photomultipliers. The dual r...

Scintillation and ionisation yields for nuclear recoils in liquid xenon above 10 keVnr (nuclear recoil energy) are deduced from data acquired using broadband Am-Be neutron sources. The nuclear recoil data from several exposures to two sources were compared to detailed simulations. Energy-dependent scintillation and ionisation yields giving acceptab...

We examine electron and nuclear recoil backgrounds from radioactivity in the ZEPLIN-III dark matter experiment at Boulby. The rate of low-energy electron recoils in the liquid xenon WIMP target is 0.75$\pm$0.05 events/kg/day/keV, which represents a 20-fold improvement over the rate observed during the first science run. Energy and spatial distribut...

The ZEPLIN-III experiment is operating in its second phase at the Boulby Underground Laboratory in search of dark matter WIMPs. The major upgrades to the instrument over its first science run include lower background photomultiplier tubes and installation of a plastic scintillator veto system. Performance results from the veto detector using calibr...

We present limits on the WIMP–nucleon cross section for inelastic dark matter from a reanalysis of the 2008 run of ZEPLIN-III. Cuts, notably on scintillation pulse shape and scintillation-to-ionisation ratio, give a net exposure of in the range 20– nuclear recoil energy, in which 6 events are observed. Upper limits on signal rate are derived from t...

The design, optimisation and construction of an anti-coincidence veto detector to complement the ZEPLIN-III direct dark matter search instrument is described. One tonne of plastic scintillator is arranged into 52 bars individually read out by photomultipliers and coupled to a gadolinium-loaded passive polypropylene shield. Particular attention has...

We present limits on the WIMP-nucleon cross section for inelastic dark matter derived from the 2008 run of ZEPLIN-III. Cuts, notably on scintillation pulse shape and scintillation-to-ionisation ratio, give a net exposure of 63 kg.days in the range 20-80keV nuclear recoil energy, in which 6 events are observed. Upper limits on signal rate are derive...

We present new experimental constraints on the WIMP-nucleon spin-dependent elastic cross sections using data from the first science run of ZEPLIN-III, a two-phase xenon experiment searching for galactic dark matter weakly interacting massive particles based at the Boulby mine. Analysis of approximately 450 kg x days fiducial exposure allow us to pl...

ZEPLIN II is a two-phase xenon detector designed to detect dark matter in the form of Weakly Interacting Massive Particles (WIMPs). Following the first 31-day underground run in Boulby Mine, UK, the collaboration published dark matter limits in January 2007; the first such limits using two-phase xenon technology. We outline the key detector design,...

A method is described that allows calibration and assessment of the linearity of response of an array of photomultiplier tubes. The method does not require knowledge of the photomultiplier single photoelectron response model and uses science data directly, thus eliminating the need for dedicated data sets. In this manner all photomultiplier working...

The ZEPLIN-III experiment in the Palmer Underground Laboratory at Boulby uses a 12kg two-phase xenon time projection chamber to search for the weakly interacting massive particles (WIMPs) that may account for the dark matter of our Galaxy. The detector measures both scintillation and ionisation produced by radiation interacting in the liquid to dif...

The ZEPLIN-III experiment in the Palmer Underground Laboratory at Boulby uses a 12kg two-phase xenon time projection chamber to search for the weakly interacting massive particles (WIMPs) that may account for the dark matter of our Galaxy. The detector measures both scintillation and ionisation produced by radiation interacting in the liquid to dif...

We present the first measurements of the muon-induced neutron flux at the Boulby Underground Laboratory. The experiment was carried out with an 0.73 tonne liquid scintillator that also served as an anticoincidence system for the ZEPLIN-II direct dark matter search. The experimental method exploited the delayed coincidences between high-energy muon...

The first measurements of the muon-induced neutron flux at the Boulby Underground Laboratory are presented. The experiment was carried out with an 0.73 tonne liquid scintillation detector that also served as an anticoincidence system for the ZEPLIN-II direct dark matter search. The experimental method exploited the delayed coincidences between high...

Data from the DRIFT-IIa directional dark matter experiment are presented, collected during a near continuous 6 month running period. A detailed calibration analysis comparing data from gamma-ray, X-ray and neutron sources to a GEANT4 Monte Carlo simulations reveals an efficiency for detection of neutron induced recoils of 94 ± 2(stat.) ± 5(sys.)%....

The first underground data run of the ZEPLIN-II experiment has set a limit on the nuclear recoil rate in the two-phase xenon detector for direct dark matter searches. In this Letter the results from this run are converted into the limits on spin-dependent WIMP-proton and WIMP-neutron cross-sections. The minimum of the curve for WIMP-neutron cross-s...

We present the first measurements of the electroluminescence response to the emission of single electrons in a two-phase noble gas detector. Single ionization electrons generated in liquid xenon are detected in a thin gas layer during the 31-day background run of the ZEPLIN-II experiment, a two-phase xenon detector for WIMP dark matter searches. Bo...

First results are presented from an analysis of data from the DRIFT-IIa and DRIFT-IIb directional dark matter detectors at Boulby Mine in which alpha particle tracks were reconstructed and used to characterise detector performance--an important step towards optimising directional technology. The drift velocity in DRIFT-IIa was [59.3 +/- 0.2 (stat)...

ZEPLIN II is a two-phase (liquid/gas) xenon dark matter detector searching for WIMP-nucleon interactions. In this paper we describe the data acquisition system used to record the data from ZEPLIN II and the reduction procedures which parameterise the data for subsequent analysis.

Recent objections (Phys.Lett. B 637, 156) to the published Zeplin I limit (Astropart. Phys 23, 444) are shown to arise from misunderstandings of the calibration data and procedure, and a misreading of the data in one of the referenced papers.

Results are presented from the first underground data run of ZEPLIN-II, a 31 kg two-phase xenon detector developed to observe nuclear recoils from hypothetical weakly interacting massive dark matter particles. Discrimination between nuclear recoils and background electron recoils is afforded by recording both the scintillation and ionisation signal...

We present details of the technical design, manufacture and testing of the ZEPLIN-III dark matter experiment. ZEPLIN-III is a two-phase xenon detector which measures both the scintillation light and the ionisation charge generated in the liquid by interacting particles and radiation. The instrument design is driven by both the physics requirements...

We present results from a GEANT4-based Monte Carlo tool for end-to-end simulations of the ZEPLIN-III dark matter experiment. ZEPLIN-III is a two-phase detector which measures both the scintillation light and the ionisation charge generated in liquid xenon by interacting particles and radiation. The software models the instrument response to radioac...

We describe the ZEPLIN II (30-kg) and ZEPLIN III (7-kg) discriminating dark matter detector using two-phase xenon designed for direct detection of cold dark matter in the form of Weakly Interacting Massive Particles. These two detectors are currently being commissioned. Both detector will begin operation in the Boulby Mine, UK in 2005. ZEPLIN II &...

DRIFT-II is a second generation multi-module gaseous dark matter detector. Each module contains two time projection chambers positioned back-to-back inside a stainless steel vacuum vessel containing carbon disulphide gas. This paper describes the DRIFT-II detector modules and the commissioning work performed to date.

The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at the Boulby Underground Laboratory (North Yorkshire, UK) ran from 2000 until 2003. A total of 44.9 kg × years of data collected with 2 encapsulated and 4 unencapsulated NaI(Tl) crystals with high light yield were included in the analysis. We present final results of this a...

We report first results from the ZEPLIN I dark matter detector, based on measurement of scintillation pulse shapes in a liquid xenon target of 3.2 kg fiducial mass. Neutron calibration shows nuclear recoil pulses to have a time constant ≅ 0.5 that of gamma and beta background events. The detector is located in the 2800 mwe depth UK Boulby Mine, and...

ZEPLIN II is a 30-kg two-phase xenon detector designed for direct detection of cold dark matter in the form of WIMPs. Currently in the commissioning phase, it will begin operation in the Boulby Mine, UK later this year. ZEPLIN II is capable of discriminating between nuclear recoils and background events and has a design reach up to two orders of ma...

The ZEPLIN I detector is a zero field liquid xenon detector used in the direct search for Galactic WIMP dark matter and has been operated at 2800mwe depth in the Boulby mine underground facility in the UK. Discrimination between the types of interaction within the liquid xenon volume is performed through measurement of the time constant of the scin...

We present results of a detailed simulation study of neutron background reduction in dark matter detectors based on observation of nuclear recoils below 100 keV. Background rates are estimated for neutrons from muons and from natural radioactivity, and with separate Monte Carlo simulations for the underground rock, shielding, and detector component...

We present and discuss the results of simulations of unshielded and shielded neutron background in underground gaseous nuclear recoil detectors for dark matter searches. Also included are measurements of the U and Th content of the rock using an unshielded Ge detector, first studies of neutron veto systems to reject neutron background from detector...

Several experimental approaches are being utilised for the direct detection of the hypothetical weakly interacting massive particle (WIMP) which constitiutes the majority of the non-luminous component of the Galaxy. These experimental techniques exploit the coherent recoil of target nucleii during a WIMP interaction and include thermal ionisation s...

DRIFT-I, the first full-scale gaseous dark matter detector, has recently been installed at ∼1100 m depth at the Boulby Underground Laboratory, UK. The DRIFT concept offers high background discrimination and sensitivity to the direction of WIMP-induced nuclear recoils, the latter being of particular importance in the search for evidence of WIMPs in...

A high flashpoint, low-toxicity liquid scintillator based on a-hydroxytoluene and containing 10 wt% Gd has been developed for solar neutrino detection and neutron measurements. Dissolution of the gadolinium compound into the scintillator was facilitated by the use of the extractant triethylphosphate. Preliminary investigation has shown the attenuat...

Detector requirements, particularly the need for background rejection, in the search for weakly Interacting Massive Particles, one of the possible solutions to the cold dark matter problem, are broadly reviewed. The use of liquid Xenon as a target material is discussed in detail for the ZEPLIN I detector, a single phase scintillation detector opera...

Measurements of cosmic-ray muon rates and energy deposition spectra in a 1t liquid scintillator detector at 1070m vertical depth in the Boulby underground laboratory are discussed. In addition, the simulations used to model the detector are described. The results of the simulations are compared to the experimental data and conclusions given. The mu...

The NAIAD (NaI Advanced Detector) experiment for WIMP dark matter searches at Boulby Mine (UK) is described. The detector consists of an array of encapsulated and unencapsulated NaI(T1) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them have been used to set new limits on the WIMP-nucleon s...

We discribe the construction status of ZEPLIN II detector, a 30-kg two-phase discriminating xenon detector to be installed in Boulby Mine, UK, for the direct detection of WIMP dark matter. Both scintillation and ionization will be measure in order to discriminate the radioactive background. ZEPLIN-II will have very high radioactive-background rejec...

The current status of the Boulby Underground Laboratory is described, with particular attention paid to the recently expanded and upgraded facilities for future underground science studies.

The neutron background at the underground laboratory at Boulby - a site for several dark matter experiments - is discussed. Special emphasis is put on the neutron background produced by cosmic-ray muons. The most recent versions of the muon propagation code MUSIC, and particle transport code FLUKA are used to evaluate muon and neutron fluxes. The r...

The neutron background at the underground laboratory at Boulby - a site for several dark matter experiments - is discussed. Special emphasis is put on the neutron background produced by cosmic-ray muons. The most recent versions of the muon propagation code MUSIC, and particle transport code FLUKA are used to evaluate muon and neutron fluxes. The r...

The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at Boulby mine (UK) is described. The detector consists of an array of encapsulated and unencapsulated NaI(Tl) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them (10.6 kg x year exposure) have been used to set upper...

Results from 75 days of data collected by the ZEPLIN I detector are presented. The detector, a 3.1kg liquid xenon target operated by the UKDMC at the Boulby mine, is described. Calibration techniques, efficiency calculations and the techniques used to remove background events are described, including the use of active turrets of liquid xenon to rej...

Statistical techniques used to analyse data from direct detection dark matter experiments are reviewed with an emphasis on general issues which could benefit from further study. In order to illustrate these issues three case studies are presented of detectors operating in different statistical regimes which require novel approaches to data analysis...

The status of dark matter searches with inorganic scintillator detectors at Boulby mine is reviewed and the results of tests with a CsI(Tl) crystal are presented. The objectives of the latter experiment were to study anomalous fast events previously observed and to identify ways to remove this background. Clear indications were found that these eve...

Thanks to new funding, the Boulby Mine Underground Laboratories are undergoing a significant expansion. These improvements have been designed primarily to meet the requirements of the Dark Matter programme, but future plans for the facility also include the possible installation of neutrino detectors. In this contribution, we describe the new facil...

This paper presents the current status and future plans for the dark matter experiments being undertaken at the Boulby mine. An array of surface controlled NaI(Tl) crystals has been constructed, which control previously observed fast anomalous signals. A series of detectors based on xenon, which has a better background discrimination potential, is...

The status of dark matter searches with inorganic scintillator detectors at Boulby mine is reviewed and the results of tests with a CsI(Tl) crystal are presented. The objectives of the latter experiment were to study anomalous fast events previously observed and to identify ways to remove this background. Clear indications were found that these eve...

The status of dark matter searches with inorganic scintillator detectors at Boulby mine is reviewed. Results of a test experiment with CsI(Tl) crystal are presented. The objectives of this experiment were to study anomalous fast events and ways to remove this background. We found clear indications that these events were due to surface contami- nati...

A Liquid Xenon based WIMP detector diagnostic array is currently developed by the UKDMC with the help of international collaborators. After a brief reminder on the detection principle in Liquid Xenon, the individual detectors will be described. ZEPLIN I, a detector with a 4 kg fiducial mass with a background discrimination based on Pulse Shape Anal...

We summarise here the present status of searches for Weakly Interacting Massive Particles at the Boulby site using NaI, liquid Xe and low pressure gas.