Strathclyde Innovation Symposium on Optically Pumped …€¦ · Strathclyde Innovation Symposium...

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1 Strathclyde Innovation Symposium on Optically Pumped Magnetometers September 25 th -26 th 2018, Ross Priory Programme and travel information

Transcript of Strathclyde Innovation Symposium on Optically Pumped …€¦ · Strathclyde Innovation Symposium...

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StrathclydeInnovationSymposiumonOpticallyPumpedMagnetometersSeptember25th-26th2018,RossPriory

Programmeandtravelinformation

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WelcomeWearedelightedyouarejoiningusforthisinnovationsymposiumonopticallypumpedmagnetometers.Thisone-offtwo-dayeventbringstogethergloballeadersinOPMresearchandcommercializationwithawiderangeofacademicandindustrialdevelopersinordertoshareideasandfosternewcollaborations.ThesymposiumismadepossiblethroughfundingforOPMdevelopmentthroughtheUKNationalQuantumTechnologiesHubinSensorsandMetrology

ThesymposiumvenueisStrathclydeUniversity’sconferencefacilityatRossPrioryonthesouthernshoreofLochLomondandweremainhopefulthatwesternScotland’sunpredictableautumnalweatherwillalloweveryonetoenjoythissceniclocation(althoughwealsoadviseyoutobringacoat).

RossPrioryThehistoryofRossPriorybeganwiththeBuchananClanduringthe11thcentury,withadwellingknowntohaveexistedonthesitefromasearlyas1693.Itisreportedthatin1745theLeith-BuchananswerecursedbytheMarquessofTullibardine,who,intheaftermathoftheBattleofCulloden,askedJamesLeith-Buchanan,5thofRoss,forshelteratthePriorybutwasinsteadbetrayedandgivenovertoKingGeorge'smen.Tullibardinecursedthemwiththeutterance:"TherewillbeMurraysontheBraesofAtholllandwhenthere’sne’eraBuchananattheRoss.”TheMarquess'scursecametopasswhen,in1925,theLeith-Buchanan'smalelinefinallydiedoutandthehousewasleasedtoMajorGeorgeJ.H.Christie,aveteranofWorldWarI,remaininginthefamily'spossessionuntilshortlyaftertheMajor'sdeath.ChristiewasresponsibleforthedevelopmentandcultivationofthePriory'ssurroundinggardens.ThePriorywassoldtotheUniversityofStrathclydein1971.Althoughtheterm"Priory"impliessomeecclesiasticalprovenance,thisisnotthecase,beingsimplya19thcenturyromanticaffectation.Thecurrentbuildingwasdesignedin1812byDunblane-bornarchitectJamesGillespieGraham(1776-1855)asanextensiveremodellingofthesite'sexistingfarmhouse.

SirWalterScottwasknowntohavevisitedseveraltimesandwroteanumberoflettersfromthehouse,andissaidtohavewrittenatleastpartof'TheLadyoftheLake'and'RobRoy'here.

RossPriorycomprisesapproximately200acresoflandandincludesaformalgarden,parkland,aburialgroundandgolfcourse.RossPrioryissituatedonthesouthernshoreofLochLomondsome25milesnorth-westofthecentreofGlasgow.ConicHill1,175'(358m)risesaboveBalmahaabout4kmacrosstheloch,andbeyondstandBenLomond3,196'(974m)andBenVorlich3,054'(931m).TheHighlandBoundaryFaultrunsthroughthenorthsideofConicHill.

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ScheduleTuesdaySeptember25th9:00am CoachtransferdepartsCollinsStreet,centralGlasgow9:45am CoachtransferdepartsGlasgowAirport10:30am ArriveRossPriory,registration&welcometovenue11:00am Session1 Developmentsinhigh-sensitivitymagnetometry

Chair Dr.PaulF.Griffin,StrathclydeUniversity 11:00am Dr.VolkmarSchultze,LeipzigIPHT

OpticallypumpedmagnetometersforoperationatEarth’sfieldstrength 11:20am Prof.PeterSchwindt,SandiaNationalLaboratory

MagneticSourceImagingUsingaPulsedOpticallyPumpedMagnetometerArray 11:40am CameronDeans,UniversityCollegeLondon

ANewMulti-PurposeQuantumImagingPlatform:AtomicMagnetometersandInductionImaging

12:00pm Dr.StuartIngleby,UniversityofStrathclydeSingle-beamdouble-resonancevectormagnetometry

12:30pm Lunch1:30pm Invitedspeaker: Dr.MichaelS.Larsen,Northrop-Grumman

SpinPolarizedAtomicSensors–DevelopingGyroscopesandMagnetometers2:30pm Invitedspeaker: Dr.VishalShah,QuSpinInc. OpticallyPumpedMagnetometers:FromLaboratorytoReal-World3:30pm Coffee&posters4:30pm Session2 High-sensitivitymagnetometryinmedicine

Chair Dr.StuartIngleby,StrathclydeUniversity 4:30pm Prof.KasperJensen,UniversityofNottingham

Magnetocardiographyonanisolatedanimalheartwitharoom-temperatureopticallypumpedmagnetometer

4:50pm Dr.MarkBason,UniversityofSussex Towardsmagnetospinographywithoptically-pumpedmagnetometers 5:10pm Prof.BenVarcoe,UniversityofLeeds MagnetocardiographyDevelopmentatCreavoMedicalTechnologies

5:30pm NiallHolmes,UniversityofNottingham Amulti-channelOPM-MEGsystem:fromconstructiontoapplication6:00pm Postersession,ScottRoom(1stfloor)7pm Symposiumdinner9:30pm Coachtransfertoaccommodation

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WednesdaySeptember26th8:15am CoachtransfertoRossPriory9am Invitedspeaker: Prof.SvenjaKnappe,UniversityofColorado

MicrofabricatedOptically-PumpedMagnetometersforNon-InvasiveBrainImaging10am Invitedspeaker: RahulMhaskar,Ph.D.,GeometricsInc. MiniatureScalarAtomicMagnetometers:AdvancesandApplications11am Coffee11:30am Invitedspeaker: ThomasW.Kornack,Ph.D.,TwinleafLLC Finite-fieldhigh-sensitivitysensors12:30pm Lunch1:30pm Optionalputting/walk/posters/coffee*3:30pm Session3 OPMtechnologiesandapplications

Chair Prof.ErlingRiis,StrathclydeUniversity 3:30pm Dr.TerryDyer,UniversityofStrathclyde MicrofabricatedVapourCellsforAtomicMagnetometry

3:50pm Dr.KamyarMehran,QueenMary,UniversityofLondonImprovingthelife-cycleandsafetyofthelithium-ionbatterypacksinelectricvehiclesusingquantummagnetometers

4:10pm Dr.MichaelTayler,UniversityofCambridge AtomicMagnetometryforNuclearMagneticResonance 4:30pm Dr.OleKock,Teledynee2v QuantumTechnologiesatTeledynee2v4:50pm Closingremarks5:00pm CoachdeparturefromRossPriory5:30pm CoachreturnstoGlasgowAirport6:00pm CoachreturnstocentralGlasgow

*RossPrioryhasa9-holegolfcourseandputtinggreen.Ballsandputtersareavailabletoborrowontheday.

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Travelinformation

GettingtoGlasgow

StrathclydeUniversityPhysicsdepartmentislocatedintheJohnAndersonBuilding,107RottenrowEast,G40NG.ThesymposiumwillbeheldattheUniversity’sRossPrioryconferencevenue(G838NL),locatedapproximately20milesfromthecityonthebanksofLochLomond. Byrail:GlasgowCentralandQueenStreetStationsarelocatedinthecitycentre,within20minutes’walkofStrathclydeUniversity.IncomingtrainsfromthesouthmainlyterminateatCentralStation,whichhasajourneytimeofapproximately5hoursfromLondonEuston.

Byair:GlasgowAirportisconnectedtothecitycentrebyafrequentbusservice(no.500)withajourneytimeof30minutes.The£12returnfarecanbepaidbycashorcardatthebusstop.EdinburghAirportisapproximately1¼hoursfromGlasgowcitycentrebybus,seehttps://www.citylink.co.uk/citylinkair.phpformoredetails.

GettingtoandfromRossPriory

Coachtransfer(AllanderTravel)isorganisedbetweenthecitycentre,airportandsymposiumvenue.TheoutwardjourneyonTuesday25thwilldepartCollinsStreet(G40NL)at9:00am,callingatGlasgowAirport(pickuppointlocatedonButeRoad,oneofthelocalswillmeetyouatthemainarrivalshall)at9:45amandcontinuingtoRossPriory.ThereturnjourneywilldepartRossPrioryattheendofthesymposium(5pmWednesday26th),callingatGlasgowAirportat5:30pm,arrivingbackatCollinsStreetat6:00pm.Coachtransferisincludedinsymposiumregistration.Theorganisersaskyoutoconfirm(ifyouhavenotalreadydoneso)whetheryourequireacoachseat,andifso,yourboardinglocation(citycentreorairport).Placesarenotlimitedbutwewouldliketoensurethatwehaveallaboard!

DelegatesarrangingtheirowntransportwillfindamplecarparkingatRossPriory,whichislocatedofftheA811DrymentoBallochroad,G838NL.

Accommodation

AccommodationisbookedforalldelegatesforTuesday25th.ThisconsistsofbedandbreakfastineithertheBuchananArmsHotel,WinnockHotelorDrymenInn,allofwhicharelocatedinDrymen.CoachtransferisorganisedbetweenRossPrioryandthesehotelsfollowingdinneronTuesday25th.AreturntransferwilldepartDrymenat8:15amonWednesday26th.

Lunch&Dinner

Buffetluncheswillbeprovidedonthe25thand26thwitharangeofvegetarianandnon-vegetarianoptions.ThesymposiumdinnerwillbeheldatRossPrioryonTuesday25th.Ifyouhavenotalreadydoneso,pleasecontacttheorganisersdirectlywithanyspecificdietaryrequirements.

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InvitedSpeakersDr.MichaelS.Larsen,Northrop-GrummanDr.MichaelLarsenreceivedhisPh.D.inphysicsfromtheUniversityofWisconsin,Madisonin2007.HeiscurrentlytheleadphysicistforquantumsensingintheAdvancedPosition,Navigation,andTimingSystemsgroupatNorthropGrummaninWoodlandHills,California.Dr.Larsen’sfocusistheapplicationofatomicphysicstothedevelopmentofhighperformance,lowsize,weightandpowersensors.HisprimaryprojecthasbeenthedevelopmentofthenuclearmagneticresonancegyroscopeunderbothDARPAandinternalfunding.Inadditionheisalsoworkingonacompactatomicvectormagnetometer,ascalaranddifferentialscalarmagnetometer,anopticalcavityreadoutaccelerometer,acoldatominterferometeraccelerometer,andanatomicclock.Dr.Larsenholds17patentsinthefieldofatomicsensorsandrelatedtechnologies,aswellas6refereedpublications.Dr.LarsenreceivedEngineeringAchievementAwardsin2009and2018fromtheSanFernandoValleyEngineers’CouncilaswellasthePresident’sLeadershipAwardin2013fromNorthropGrummanforhisroleastheprincipalinvestigatorontheNuclearMagneticResonanceGyroscopeandotherquantumsensingresearchanddevelopmentteams.SpinPolarizedAtomicSensors–DevelopingGyroscopesandMagnetometersNorthropGrummanhasbeendevelopingspinpolarizedatomicsensorssince1967.TheworkstartedwiththedevelopmentofaNuclearMagneticResonanceGyroscope(NMRG)usingthennewtechniquesofspinexchangeopticalpumpingandco-magnetometry.Offshoottechnologiessoonfollowedincludingmagnetometersandatomicclocksleveragingthecommonsupportingtechnologies.Thispresentationwilldescribethedevelopmenthistory,underlyingphysicsofoperation,commonsupportingtechnologies,andcurrentstatusoftheNMRGandrelatedoffshoottechnologies.Dr.VishalShah,QuSpinInc.Dr.VishalShahiscurrentlytheFounderandChiefScientistatQuSpin.PriortofoundingQuSpinin2012,Dr.ShahworkedasaPhysicistatSymmetricom(nowMicrochip)from2009to2012ondevelopingacompactcoldatomclock.Dr.ShahreceivedaPh.D.inAMOphysicsforhisworkonchip-scaleatomicclocksandmagnetometersatNIST/UniversityofColoradoin2007.Subsequenttograduatestudies,Dr.ShahworkedasapostdoctoralresearcherinRomalisgroupatPrincetonwherehisresearchfocusedonimprovingtheperformanceofatomicdevicesusingquantumnon-demolitionmeasurements.OpticallyPumpedMagnetometers:FromLaboratorytoReal-WorldInmytalk,IwillgiveanoverviewoftheworkatQuSpinondevelopingcommercialgradeopticallypumpedmagnetometers(OPM).Specifically,Iwilldiscussthecurrentstatusofourzero-fieldandscalarOPMtechnology,andourviewonthetechnicalpotentialofthistechnologyinthenextfiveyears.Iwillalsoshareourexperienceintakingthistechnologyfromlaboratorytocommercialdomain.

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Prof.SvenjaKnappe,UniversityofColorado,BoulderSvenjaKnappereceivedherPh.D.inphysicsfromtheUniversityofBonn,Germanyin2001withathesisonminiatureatomicmagnetometersandatomicclocksbasedoncoherent-populationtrapping.For16years,sheworkedattheNationalInstituteofStandardsandTechnology(NIST)inBoulderCO,developingchip-scaleatomicsensors.SheisnowanAssociateResearchProfessorattheUniversityofColoradoandherresearchinterestsincludemicrofabricatedatomicsensors.Sheisalsoaco-founderofFieldLineInc.MicrofabricatedOptically-PumpedMagnetometersforNon-InvasiveBrainImagingWepresentourongoingeffortindevelopingimagingsystemswithmicrofabricatedoptically-pumpedmagnetometers(µOPMs).Byuseofmicrofabricationtechnologiesandsimplificationofopticalsetups,weaimtodevelopmanufacturablesensorsofsmallsizeandlowpower.Ourzero-fieldµOPMsrequireashieldedenvironmentbutreachhighsensitivitiesoflessthan10fT/Hz1/2.Targetapplicationslieinthefieldofnon-magneticbrainimaging,specificallymagnetoencephalography(MEG).Theattractionofusingthesesensorsfornon-invasivebrainimagingcomesfromthepossibilityofplacingthemdirectlyonthescalpofthepatient,veryclosetothebrainsources.Wehavebuiltseveralmulti-channeltestsystemstovalidatethepredictionofveryhighsignal-to-noiseratiosinstandardMEGparadigms.Dr.ThomasW.Kornack,ChiefScientist,TwinleafLLCDr.Kornackisanexpertinthedesign,fabricationandoperationofmagnetometersandgyroscopes,withoversevenyearsofresearchinthefieldandauthorshipongroundbreakingpublications.DuringgraduateandpostdoctoralworkatPrincetonUniversity,hehasworkedonmanyimportantprojects,includingthedevelopmentofthefirstSERFmagnetometers.Forhisdissertation,hebuiltahigh-performanceco-magnetometertoprobefundamentallawsofphysicsandforuseasasensitivegyroscope.In2007,Dr.KornackfoundedTwinleaftodevelopandcommercializethesesensorsforuseinawidevarietyofapplications.Twinleaf'scoretechnologicalbasisisderivedfromhisextensiveexperiencebuildingtheworld'smostsensitivemagneticfieldsensors.Finite-fieldhigh-sensitivitysensorsModernalkalimetalsensorsachievebothhighperformanceandsmallersizethankstobreakthroughsinsuppressingtheeffectsofspin-exchangecollisionsamongatoms,bothatzerofieldandnowatfinitefield.WhilezerofieldSERFmagnetometerswithlessthan10fT.Hz-1/2sensitivityarenowanestablishedtechnique,achievingthesameperformanceatfinitefieldisanexcitingnewdevelopment,potentiallyobviatingtheneedforcostlymagneticshielding.IreviewthehistoryofthisfieldanddiscusscommercialdevelopmentofsensorsatTwinleaf.

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RahulMhaskar,Ph.D,GeometricsInc.Dr.RahulMhaskarisVicePresidentforResearchandDevelopmentatGeometrics,amanufacturerofgeophysicalinstrumentationwithworldwidepresence.HeearnedhisPh.D.inAppliedPhysicsfromtheUniversityofMichiganunderthedirectionofProf.GeorgRaithel.AfterabriefstintatHarvardUniversity,hejoinedtheTimeandFrequencyDivisionattheNationalInstituteofStandardsandTechnologyinBoulder,COasapostdoc,workingwithDr.JohnKitchingandDr.SvenjaKnappeonChip-ScaleAtomicMagnetometers.WhileatNIST,hedevelopedmicrofabricatedfiber-coupledSERFmagnetometersandwasamongthefirstresearcherstodemonstratethemagnetoencephalographyusingtheseuncooledsensors.Subsequently,hetookapositionatGeometricstoleadthedevelopmentofhighlypreciseminiaturescalarmagnetometersforgeomagneticmeasurements.Usingthesesensors,hedemonstratedmeasurementofmagnetocardiographyinacommercialenvironment.Havingoverseenthedevelopmentofminiaturemagnetometersfromconcepttoamanufacturedproduct,heisnowfocusedonapplyingtheirlowpayloadsignaturecapabilitytogeomagneticsurveysusingautonomousplatformssuchasdronesandautonomousunderwatervehicles.MiniatureScalarAtomicMagnetometers:AdvancesandApplicationsScalarmagnetometersareusedtomakeveryprecisemeasurementsofsmalldeviationsintheEarth’sfieldtodetectawidevarietyofobjectsrangingfrompipesandunexplodedordnance(UXO)tosubmarines.AtomicmagnetometersaretypicallyusedasthesensorofchoiceinmeasuringthemagnitudeoftheEarth’smagneticfieldthroughtheLarmorprecessionofatomicspins.Overthepastfivedecades,scalaratomicmagnetometrytechnologyhasreliedonradiofrequency(RF)magneticfieldstodrivetheLarmorprecessionandRFdischargelampsasthelightsourcetodetecttheprecession.Withinthepasttenyears,VerticalCavitySurfaceEmittingLaser(VCSEL)technology,developedforchipscaleatomicclocks,hasenabledsignificantminiaturizationoftheatomicmagnetometerswithcommensuratedecreaseinpowerconsumption.Theminiaturemagnetometersnowallowintegrationofthesesensorsinnumerousapplicationswhereearlier,thesizeandweightofthelamp-basedsensorsprecludedtheiruse.Inthistalk,IpresentanoverviewofscalaratomicmagnetometerdevelopmentatGeometrics.Ifurtherpresenttheapplicationofthesesensorsingeophysicalmeasurementsandbeyond,touchinguponmagnetocardiography,non-destructivetestingofconductivebulkmaterials,andinfrastructuremonitoring.Theconvergenceofanumberoftechnologiesincludingthedevelopmentofautonomousplatforms,heuristicanalysesoflargedatasets,andubiquitouscomputingopensupsubstantiallynewapplicationareasfortheminiatureatomicmagnetometerswithseeminglyunendingpossibilities.

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Abstracts

Optically pumped magnetometers for operation at Earth’s field strength

Volkmar Schultze1, Rob IJsselsteijn2, Christian B. Schmidt1, Gregor Oelsner1, Florian Wittkämper1, Ronny Stolz1

1 Leibniz Institute of Photonic Technology (Leibniz-IPHT), Albert-Einstein-Straße 9, 07745 Jena, Germany

2 Supracon AG, An der Lehmgrube 11, 07751 Jena, Germany

The development of Optically Pumped Magnetometers (OPM) at Leibniz-IPHT especially intends to address applications such as geophysical prospection or biomagnetic measurements without magnetic shielding. Thus, the magnetometers have to be operable in Earth’s field without compromises in dynamic range and magnetic field resolution. These applications require the use of multiple sensor elements rather than a single OPM. As a consequence, assemblies of multiple alkali vapor cells with stable and mutually referenced properties on a single chip are used, thus also enabling new operational modes and complex magnetic-field characterization. With advanced micro-systems technologies adapted from earlier NIST developments [1] and improved at the Leibniz IPHT [2,3] long-term stable OPM cell assemblies using micro-structured silicon substrates enclosed with anodically bonded glass plates are produced. The Figure shows two examples of OPM cell arrays used herein.

In order to achieve good magnetic-field sensitivities despite the small cell volume of only several ten cubic millimeters, new operational modes have been developed as an alternative to spin-exchange relaxation-free (SERF) operation as this method is not operable in magnetic fields of several 10µT such as the Earth’s field. Using strong detuned pumping, light-narrowing (LN) is achieved, which reduces the shot-noise limited magnetic-field resolution Bsn achieved with the small cells from 200 fT/�Hz in the conventional Mx mode down to 40 fT/�Hz in the LN mode [4]. The combination of the signals of appropriately operated identical cells can improve the signal quality further. Thereby, we introduced the new light-shift dispersed Mz (LSD-Mz) mode for which the shot-noise limited resolution, using the same OPM cells, can be reduced down to about 10 fT/�Hz providing a bandwidth from DC to several hundred Hertz [5]. With appropriately adapted vapor cell layouts and operational modes various applications are addressed, as – for example – biomagnetic characterization and imaging at humans and animals.

[1] L. Liew et al., Appl. Phys. Lett. 84, 2694 (2004). [2] S. Woetzel et al., Rev. Sci. Instr. 82, 033111 (2011). [3] S. Woetzel et al., Surface & Coatings Technology 221, 158 (2013). [4] T. Scholtes et al., Optics Express 20, 29217 (2012). [5] V. Schultze et al., Sensors 17, 561 (2017).

Integrated cesium vapor cell assemblies with common cesium reservoir in 4 mm thick silicon substrates. Left: Four locally separated 4 mm wide magnetometer cells; Right: Gradiometer consisting of two wide magnetometer cells.

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Magnetic Source Imaging Using a Pulsed Optically Pumped Magnetometer Array

Amir Borna1, Tony R. Carter1, Paul DeRego2, Conrad D. James1, Peter D. D. Schwindt1

1 Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185-1082, USA 2 Kansas City National Security Campus, 2450 Alamo Ave SE, Albuquerque, NM 87106

We have developed a pulsed optically pumped magnetometer (OPM) array for detecting magnetic field maps originated from an arbitrary current distribution. The presented magnetic source imaging (MSI) system features 24 OPM channels, has a data rate of 500 S/s, a sensitivity of 0.8 𝑝𝑇/√𝐻𝑧, and a dynamic range of 72 dB. We have employed our pulsed-OPM MSI system for measuring the magnetic field map of a test coil structure. The coils are moved across the array in an indexed fashion to measure the magnetic field over an area larger than the array. The captured magnetic field maps show excellent agreement with the simulation results. Assuming a 2D current distribution, we have solved the inverse problem, using the measured magnetic field maps, and the reconstructed current distribution image is compared to that of the simulation.

Fig. 2. Current distribution imaging using simulated (a) and measured (b) magnetic fields. The coil structure is overlaid on top of the constructed current density vectors.

Fig. 1. The magnetic sensor array inside the three-layer magnetic shield. PD TIA: transimpedance amplifiers of the photo diodes; ADC: analog-to-digital-converter; DAC: digital-to-analog-converter; device under test (DUT) Sig.: the signal driving the device under test; Mod. Sig.: the control signal modulating the laser system, the bias field, and the polarizing magnetic field.

Fig. 3. The dependency of the constructed current density image quality on the measurement distance (𝑧0) and array’s sensor spacing normalized to the length of the side, L: a) the correlation between the original current carrying trace and the constructed current density image; b) the 1-cm wide original current carrying trace with a side length of 30 cm; c-d) the constructed current density image for a correlation of 70 % and 25 % respectively.

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ANewMulti-PurposeQuantumImagingPlatform:AtomicMagnetometersandInductionImagingC.Deans,L.Marmugi,F.RenzoniDepartmentofPhysicsandAstronomy,UniversityCollegeLondon,GowerStreet,LondonWC1E6BTWepresentanon-invasivesensingandimagingsystembasedonatomicmagnetometers(AMs)operatinginmagneticinductiontomography(MIT)modality.AnACmagneticfieldinduceseddycurrentsinthesampleofinterest,probingitsconductivity.Theresponseismappedwithradio-frequencyAMs.Theirsuperiorperformance-intermsofsensitivity,tunability,unshieldedandroom-temperatureoperation-makesRFAMstheidealchoiceformovingthedevicetooutdoorapplications.Inparticular,theirsensitivityallowsdetectionandimagingofnon-magnetic,low-conductivetargets.Thepossibilityofarbitrarilychoosingtheoperatingfrequencyallowspenetrationofconcealingbarriersandremotedetection,potentiallyuptoseveralkilometresandunderwater.Thispavesthepathtowardsanewgenerationofnon-invasive,non-destructiveandultra-sensitiveimagingplatformsformulti-purposeapplications.Inthistalk,wewillreportontheongoingresearchatUCLaimedattheapplicationofthenewsensingplatformtonon-destructiveevaluationofmaterials,industrialmonitoring,defenceandsecurity,andbiomedicalimaging.Wewillshowdemonstrationsof:imagingofmetallicandnon-metallictargets;penetrationofthickbarriers;2x2arrayoperation;andremotedetectionandlocalisationinairandunderwater.Themostrecentdevelopmentswhichledthetotherecordsensitivityof100fT/Hz1/2,withasinglesensorinanunshieldedenvironment,andthefirstapplicationofmachinelearningtoAMsandelectromagneticinductionimagingwillbepresented.Finally,perspectivetowardstherealizationofaconductivitymapoftheheartforthediagnosisofatrialfibrillationwillbediscussed.

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Single-beam Vector Magnetometry Exploiting Orientation-Phase Effects in a Double-Resonance Sensor

Stuart J. Ingleby1, Carolyn O’Dwyer1, Paul F. Griffin1, Aidan S. Arnold1 and Erling Riis1 1. Department of Physics, SUPA, Strathclyde University, 107 Rottenrow East, Glasgow

Conventional double-resonance magnetometry yields a scalar measurement of the static field magnitude B0, through measurement of the resonant response to a modulation field BRF at a frequency ωRF close to the atomic Larmor frequency ωL [1]. We present detailed experimental data and atomic polarisation models for the observed amplitude and phase of double-resonance magnetometer signals under arbitrary orientations of B0 [2]. Further, we demonstrate a unique mapping between the phase of the first- and second-harmonic signal components and B0 orientation, allowing determination of the field vector from demodulated on-resonance data. 6

FIG. 7. Measured and set magnetic field magnitude and orientation for a wide range of ~B0 orientations. Observed values anduncertainties for ✓V and ✓L are calculated from �1f

0 and �2f0 using Equations 15 and 16. The point of best angular resolution is

measured at (|B0| = 199.8445(17) nT , ✓V = 100.986(27)� , ✓L = 118.198(24)� ). The inset in the lower left corner shows the

contour described by successive ~BAPP orientations, plotted using the same projection as Figures 5 and 6.

tan ✓L =� cos ✓V

cos 2✓V tan�1f

0

(16)

By measuring the resonant response of the detectorsignal, demodulating to obtain the first- and second-harmonic signal amplitude and phase, and fitting to de-termine the Larmor frequency and on-resonance phases,we can calculate ✓V and ✓L and make a full-vector mea-surement of ~

B

0

.

Figure 7 shows calculated ✓V and ✓L for a range of ~

B

0

orientations defined using the calibrated Helmholtz coilsystem. The range of orientations is shown as an insetto Figure 7 and was chosen to scan over the zone of highsignal amplitude around the light polarisation (x -) axis.At each point the first- and second-harmonic resonanceresponses are measured for a range of x and fitted usingEquations 6 - 9. The on-resonance phases �1f

0

and �

2f

0

arefree parameters in this model, and the fit uncertaintiesare propagated through Equations 15 - 16 to give theuncertainties in ✓V and ✓L. The point of highest observedangular resolution has uncertainties of �|B

0

| = 1.7 pT,�✓V = 0.027�, �✓L = 0.024�, giving an overall angularresolution at this point of �✓ = 0.036� (0.63 mrad).

CONCLUSIONS

The measurement of complementary field orienta-tion information using a hitherto-scalar double-resonancemagnetometry technique has clear potential for impact inpractical measurements of arbitrarily oriented fields. Ex-isting three-axis magnetometer data is often transformedto derive data on field magnitude, declination and incli-nation. In this work we demonstrate a scheme for inde-pendent measurement of the field vector in this spher-ical polar basis, while also exploiting the precise andaccurate measurement of field magnitude possible withthe double-resonance technique. The single-beam, RF-modulated detection scheme used is imminently suitablefor scalable, portable devices.

The data shown in Figure 7 demonstrate resolution ofthe magnetic field magnitude at the pT-level and mag-netic field orientation at the sub-mrad level. The vari-ation of the measured field magnitude and orientationfrom the expected field magnitude (200 nT) and orien-tation (solid lines) exposes residual calibration errors inthe Helmholtz coil system, which can set ~

B

0

with toler-ances in the 100-pT and few-mrad ranges. The generalvalidity of the phase-orientation e↵ects derived from the-

Fig. 1 Measured and set magnetic field magnitude and orientation over a wide range of range of B0 orientations. The point of best angular resolution is measured at |B0| = 199.8445(17) nT, θV = 100.986(27)°, θL = 100.986(27)°. The inset figure shows the contour described by B0 orientations around the axis of maximum magnetometer sensitivity.

We discuss the potential applications of this technique and the current limitations on resolution and bandwidth, as well as hardware developments for portable unshielded systems. This work is supported by the EPSRC Quantum Technology Hub in Sensors and Metrology [3].

References [1] A. L. Bloom, Principles of Operation of the Rubidium Vapor Magnetometer, Applied Optics 1, 61 (1962) [2] S. J. Ingleby, C. O’Dwyer, P. F. Griffin, A. S. Arnold, and E. Riis, Orientational effects on the amplitude and phase of polarimeter

signals in double-resonance atomic magnetometry, Phys. Rev. A 96, 013429 (2017) [3] www.quantumsensors.org

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Towardsmagnetospinographywithoptically-pumpedmagnetometersDr.MarkBason,UniversityofSussexThelastdecadeshaveseensignificantattentioninmeasurementsofbio-magneticactivityfromtheheartandbrain.Extendingthesestudiestoincludethespinalcordwilloffersignificantopportunitiesforclinicalstudiesinarangeofdiseasesandconditions.Inthistalk,IwilllookattheperspectivesformeasurementsofthespinalcordwithOPMsanddiscusstheiradvantagesoverSQUID-basedsystemsandequivalentelectricalmeasurements.IwilldiscussourplansatSussexfortwosuchmeasurements:theevolutionofpathologicalmarkersfollowinganearlymultiplesclerosisattackandestimationsofcentralsensitisationinpatientswithneuropathicpain.

Magnetocardiography on an isolated animal heart with a room-temperature optically pumped magnetometer

Kasper Jensen1,*, Mark Alexander Skarsfeldt2, Hans C. Stærkind1, Jens Arnbak1, Mikhail V. Balabas1,3, Søren-Peter Olesen2, Bo Hjorth Bentzen2, Eugene S. Polzik1

1 Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark. 2Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark. 3Department of Physics, St Petersburg State University, Universitetskii pr. 28, 198504 Staryi Peterhof, Russia *current address: School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, England, United Kingdom.

Optically pumped magnetometers are becoming a promising alternative to cryogenically-cooled superconducting magnetometers for detecting and imaging biomagnetic fields. Magnetic field detection is a completely non-invasive method, which allows one to study the function of excitable human organs with a sensor placed outside the human body. For instance, magnetometers can be used to detect brain activity or to study the activity of the heart. We have developed a highly sensitive miniature optically pumped magnetometer based on cesium atomic vapor kept in a paraffin-coated glass container. The magnetometer is optimized for detection of biological signals and has high temporal and spatial resolution. It is operated at room- or human body temperature and can be placed in contact with or at a mm-distance from a biological object. With this magnetometer, we detected the heartbeat of an isolated guinea-pig heart, which is an animal widely used in biomedical studies. In our recordings of the magnetocardiogram, we can in real-time observe the P-wave, QRS-complex and T-wave associated with the cardiac cycle. We also demonstrate that our device is capable of measuring the cardiac electrographic intervals, such as the RR- and QT-interval, and detecting drug-induced prolongation of the QT-interval, which is important for medical diagnostics.

Reference: K. Jensen et al. Magnetocardiography on an isolated animal heart with a room-temperature optically pumped magnetometer. arXiv:1806.10954 (2018)

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MagnetocardiographyDevelopmentatCreavoMedicalTechnologiesBenVarcoe,UniversityofLeedsandCreavoMedicalTechnologies

Cellularactionpotentialsoriginatinginmyocardialcellsgenerateelectricalactivityintheheart,buttheyalsocreatemagneticfields.Changesinperfusion(bloodsupply)affecttheactionpotentialleadingtocommensuratechangesinthemagneticfield.Mappingthecardiacmagneticfieldthereforecreatesasignalthatreflectstheextentofchangeinactionpotentialwithintheheart.SinceboththeECGandMCGaredetectingsignalsgeneratedbythesameelectricalactivityoftheheart,MCGcanbeconsideredthemagneticequivalentofanECG.However,theMCGhasanumberofkeyadvantages,withoneexamplebeingthatthemagneticfieldisnotdiffusedordispersedbytissue.WhilethemagneticfieldsareextremelysmallamagneticfieldmapisneverthelesscapableofdifferentiatingbetweennormalandabnormalcardiacbehaviourandhasbeenshowninclinicaltrialstoprovideusefulanddifferentinformationthanECGoverarangeofcardiacconditions.Thereasonforthisisthatalocalisedproblemintheheart,suchasnecrosisorischaemia,disruptsthemagneticfieldimpactsanddistortstheentiremagneticfieldandthushasasignificanteffectontheMCGscan.Ahealthcareprofessionalthatisfamiliarwithanormalscanmightthereforebeabletoidentifydifferentcardiacconditionsbystudyingtheresultantmagneticmaps,waveformsandnumericaldataproduced.However,giventhatthereareanumberofwaysthatthemagneticfieldoftheheartcanbeimpactedbychangesatacellularlevel,theeasiestdiagnosistomakeis“normal”.Thisisunusualinmedicinewheretheaimisnormallytofindtheproblem,however,inanemergencydepartmentwithapatientpresentingwithapotentiallylifethreateningcondition,thediagnosisof“normal”savesstress,timeandmoney.Animmediateandvaluableapplicationistousemagnetocardiographytopositivelyfilteroutthe“worriedwell”intheemergencydepartment.Howeverdevelopingadevicethatisusefulinthiscontextistricky,becauseitneedstoberapidlyandeasilydeployedatthepatient’sbedsidebysomeonewithminimaltraining.Itneedstobelight,mobileandrobust.Itthereforeneedstobebothsufficientlysensitiveandsufficientlyimmunetothetypesofelectricalandmechanicalnoisethatarepresentinanoisyemergencydepartmenttobeabletodeliveramedicallyvalidresponse.Thisisanextremelychallengingenvironmentforprecisionsensors,shieldingisimpossibleandthebedsaretypicallymadeofferromagneticmaterial.Awiderangeofsensorshavebeenusedformagnetocardiography,includinginductioncoil,SQUID,atomicphysicsandsolidstatesensors,allofwhicharesufficientlysensitive.Thedifficultyisinmakingthemimmunetonoise.Hence,themainaimofourresearchoverthelast15yearshasbeenthedevelopmentofsensorarrangementsandsignalprocessingsolutionsthatenablesmagnetocardiographytobeperformedinsuchenvironments.Thisworkhasbeencommercialisedbyastart-upcalledCreavoMedicalTechnologiesandwenowhavedevicesinmorethanadozenlocationsintheUK,GermanyandUSAcollectingpatientdatainemergencydepartmentsandthousandsofpatientscans.Thistalkwilldiscussthechallengesandsomeoftheelementsthathavegoneintodevelopingasolution.

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Amulti-channelOPM-MEGsystem:fromconstructiontoapplicationNiallHolmes1,JamesLeggett1,ElenaBoto1,RyanMHill1,GillianRoberts1,TimMTierney2,VishalShah3,RebeccahSlater4,GarethRBarnes2,RichardBowtell1andMatthewJBrookes11)SirPeterMansfieldImagingCentre,UniversityofNottingham.2)InstituteofNeurology,UniversityCollegeLondon.3)QuSpinInc.,ColoradoUSA.4)DepartmentofPaediatrics,UniversityofOxford.

Magnetoencephalography(MEG)isanon-invasivemeasureofbrainfunctionwithhightemporalandspatialresolution.TraditionalMEGdevicesarecooledwithliquidheliumandrequiresubjectstoremainstillwithinafixedsensorarraylimitingthesubjectgroupswhichcanbestudied,andexperimentswhichcanbeperformed.RecentlywehaveshownaMEGdeviceemployingopticallypumpedmagnetometers(OPMs)whichallowshighqualitydatatobecollectedduringlargesubjectmotions[1,2].TheQuSpinOPMhasanoisefloorof15fT/√Hzbutalsoanarrowdynamicrangeof±1.5nT:anymovementsthroughthespatiallyinhomogeneousremnantmagneticfieldinsideamagneticallyshieldedroom(MSR)quicklysaturatesmeasurements.Toaddressthisissueafieldcompensationsystemwasconstructedtonullthisfieldandallowlargesubjectmovements[2].ThecoilcurrentsarecontrolledbyareferencearrayofOPMsallowingforreductionofthedominantcomponentoftheremnantfieldbyafactorof~45anddominantgradientbyafactorof~13.ThepositionsandorientationsoftheOPMswithrespecttothesubject’sbrainarerequiredforsourcereconstruction.Thisinformationiscurrentlyobtainedusingsubject-specific,3Dprintedscanner-castswhicharebothbulkyandexpensivetoproduceonasubjectbysubjectbasis.AsafirststeptowardsmoregenericdesignswehaveemployedadaptedbicyclehelmetswheresensorlocationscanbeobtainedviaanX-Rayofthehelmetco-registeredtoadigitisationofthesubject’shead.Preliminaryresultsusingthesehelmetsshowarobustneuralresponsecanbeobservedinthreesubjectsaged2,5and24.ThisisacrucialfirststepinrealisingthepotentialofOPM-MEGtoinvestigatethedevelopingbrain.Theincorporationofthesystemwithvirtualrealityheadsetsisalsobeinginvestigatedtoprovideamorenaturalisticenvironmentinwhichtostudythebrain.[1]Botoetal.,Nature2018.[2]Holmesetal.,NeuroImage2018.

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Improvingthelife-cycleandsafetyofthelithium-ionbatterypacksinelectricvehiclesusingquantummagnetometersDr.KamyarMehran,QueenMaryUniversityofLondonOnlineconditionmonitoringofthexEVbatterymodulebyfarisadifficultproblem.Themonitoringiscrucialtoincreasethelife-cycleofthebatterypacksandeliminatethepossibilityofbatteriesoverheatingandcausingfires,whichremainsanimportantconsumerconcern.Thedirectmeasurementofthecriticalbatterycellparameters,i.e.state-ofcharge(SoC),state-of-health(SoH),andtemperature,hasnotyetbecomepossibleandallthesophisticatedestimationtechniquessuggestedishardtobepracticallyembeddedinthebatterymanagementsystem(BMS).Weproposetouseanemergingquantumsensortechnology,i.e.quantummagnetometerarray,tomeasurethecurrentflowthroughEVbatteries.Withthehelpofthearray,wecharacterisecurrentirregularitiesduringiontransferforcharging/dischargingandgenerateimagestobeencodedintheBMSusingnoveldataprocessingsystem.ThisnewgenerationofBMSwillmaintainanaccurateandtimelyestimateofthecriticalparameterstoeffectivelyincreasethelife-cycleofthebatterypacksandprovidetherequiredsafetyforspeciallybatteryelectricvehicles.Atomicmagnetometersfornuclearmagneticresonance(NMR)MichaelTayler,MagneticResonanceResearchCenter(MRRC),DepartmentofChemicalEngineeringandBiotechnology,UniversityofCambridge,UK,mailto:[email protected],[email protected](OPMs)thatreachsensitivitiesof<20femtotesla/Hz1/2areeasilycapableofdetectingthemagneticfieldproducedbypolarized1H,13Candseveralothermagneticallyactivenucleiinmatter.Overthepast10-15yearsthishasstimulatedthedevelopmentofopticalmagnetometersfornuclearmagneticresonancespectroscopy(NMR)andmagneticresonanceimaging(MRI),twoindispensabletoolsforanalyzingtheinternalstructure,chemistryanddynamicsofsoftmatter.WhatisthefutureofOPMsinNMR?NMRspectroscopyhastrendedoverits70+yearhistorytowardsverystrongmagneticfieldsof10-20tesla.Inthesefields,induction-coildetectionofNMRsignalsismanyordersofmagnitudemoresensitivethanthebestOPMs,andresolvedchemicalshiftscanbeusedformolecularidentification/quantitationinmixturescontaininghundredsofdifferentcompounds.Toaddresstheabovequestion,myshorttalkwillhighlightthevalueofOPMsindetectingNMRinthenTtomTrange.Iaminterestedintheprocessesbywhichpolarizednucleireturntothermalequilibriumundertheseconditions(i.e.relaxationrates)andtheinformationtheyprovideoninter-molecularandintra-moleculardynamicsinliquids.AtCambridgewehavebuilta“minimalist”OPMoperatingvianonlinearmagneto-opticalrotation(NMOR)inspin-exchange-relaxation-free(SERF)rubidium87andopen-sourcetoolsincludingthepopularArduinofamilyofmicrocontrollers.ThissetupisusedtodetectNMRsignalsfromsmallquantitiesofliquid(~50uL)imbibedintoporouscatalystsupportmaterials.Bymeasuringtherelaxationduetotransientadsorptionatthesurfacesites,inlowmagneticfield,weseektoimproveunderstandingofhowmoleculesbehaveinconfinedspacesandatsurfaces.

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PostersPosterswillbepresentedintheScottRoomupstairsonthefirstfloorofthebuilding.PosterboardsareA0,portraitorientation.

An on-scalp MEG system based on optically-pumped magnetometers

Rasmus Zetter

1⇤, Joonas Iivanainen

1⇤, Lauri Parkkonen

1,2

1. Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland

2. Aalto NeuroImaging, Aalto University, Espoo, Finland

Magnetoencephalography (MEG) is a non-invasive functional neuroimaging method for investigating electricneuronal activity of the living human brain. The magnetic field produced by neural currents is measured usingsensors positioned around the head. Here we describe an on-scalp MEG system using optically-pumped magne-tometers (OPMs).

Recently developed OPMs have high enough sensitivity to be applied for MEG, and do not require the same de-gree of thermal insulation as low-Tc SQUIDs. Thus, OPMs can be placed almost directly on the scalp, considerablyboosting both the sensitivity to neural sources as well as spatial resolution in comparison to conventional SQUID-based MEG in which the sensors are 2–3 cm away from scalp [1,2]. For practical OPM-MEG measurements, weapply OPMs (QuSpin Inc., Louisville, CO, USA) in a rigid sensor helmet with identical geometry to that of theMEGIN (MEGIN Oy, Helsinki, Finland) SQUID-based MEG system. Individual OPMs are placed into sockets,whose positions and orientations correspond to those of the MEGIN system, and inserted until touching the headof the subject. For data acquisition, we use a modified MEGIN data acquisition system, which enables conve-nient usage in a well established workflow, including online averaging and data analysis (e.g. for brain–computerinterfaces).

To enable source estimation, one needs to co-register the MEG data to MRI. Accurate co-registration is par-ticularly important in on-scalp MEG [3] due to its high spatial resolution. In our OPM-MEG system, we apply astructured-light scanner to digitize the subject head surface together with the sensor helmet. This digitized surfaceis then aligned to the head surface derived from the subject’s MR image, as well to the known geometry of thesensor helmet.

Our OPMs – operating in the spin exchange relaxation-free (SERF) regime – require the absolute magneticfield to be small in order to achieve high sensitivity. We apply a set of large coils to actively control the magneticfield up to the first-order gradients over a volume to address the following issues. First, the coil system can null thestatic field within this head-sized volume to minimize field changes experienced by OPMs due to their movementwith respect to the remanent field (e.g., movement of the subject’s head with OPMs attached). Second, it candynamically compensate the field based on OPM outputs to remove slow field changes due to head movement andtemporal drifts of the field. We highlight the importance of operating OPMs under negative feedback to ensuresufficient calibration accuracy for MEG. We implemented negative feedback using a large coil set; however, alsoapplying feedback internally in each sensor would provide even better calibration accuracy.

We have successfully recorded both evoked and induced brain responses to visual, auditory and somatosensorystimulation with this set-up.

References

[1] E. Boto, R. Bowtell, P. Kruger, T. M. Fromhold, P. G. Morris, S. S. Meyer, G. R. Barnes, and M. J. Brookes, ”On the Potential of a NewGeneration of Magnetometers for MEG: A Beamformer Simulation Study,” PLoS One, vol. 11, no. 8, p. e0157655, Aug. 2016.

[2] J. Iivanainen, M. Stenroos, and L. Parkkonen, ”Measuring MEG closer to the brain: Performance of on-scalp sensor arrays,” NeuroImage,vol. 147, no. December 2016, pp. 542–553, Feb. 2017.

[3] R. Zetter, J. Iivanainen, M. Stenroos, and L. Parkkonen, ”Requirements for Coregistration Accuracy in On-Scalp MEG,” Brain Topogr.,Jun. 2018.

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BalancedplanarcoilsformagneticfieldcompensationinwearableMEGNiallHolmes,UniversityofNottinghamConstructionofanOPM-basedMEGsystemDr.JamesLeggett,UniversityofNottinghamUnshieldedAtomicMagnetometry;BuildingaPortable,CompactDeviceCarolynO’Dwyer,UniversityofStrathclydeAtomicmagnetometrycanbeusedtomeasuremagneticfieldswithunshieldedsensitivitiesinthetensoffemtoTesla.[REF]Inordertomovefromwellestablishedlab-basedexperimentstofield-readyinstrumentswearedevelopinganunshielded,portableMxmagnetometerforuseinarangeofenvironments.ThedoubleresonancetechniquepresentedhereusesasinglelaserbeamtopumpthermalcaesiumvapouraswellasphasesensitivelyprobeitscoherentprecessioninthepresenceofanRFfield[2].Weaimtominimisehardwarewhileprioritisingsub-picoTeslasensitivities.Herewedescribetechniquestomaximisesensitivity,includingactivenoisecancellationandvapourcelloptimization.ApplicationofSERFmagnetometrytoNuclearThreatReduction.AbigailLangley,RobertWard,MaximJoseph,JosephWatsonTheNuclearThreatReductionprogrammeatAWEistaskedwithenhancingthedetectionofradiologicalandthreatobjectstostrengthenbordersecurity.Aparticularchallengeistheimagingofobjectswithinsealedenclosures.Thisiscrucialinthescanningofbagsatairports,orfastparcelscanninginfreightoraspartofthepostalservice.TheseparticularissuesaretraditionallymetwithX-rayradiographytechniques,however,magneticimagingisconsideredasanon-ionisingcomplimentarymethod.ThisworkintroducestheutilisationofaQuSpinZero-FieldatomicmagnetometerinlowfrequencyEddyCurrentInduction(ECI)forthedetectionofconductiveobjectsinshieldedconfigurations.Thepresenceofacopperdisc(5mmdiameter,3mmthick)wasdetectedbehindaluminiumbarrierswithacombinedthicknessof17mm.Thiswasachievedatfrequencies<150Hz.Thepresenceofthediscwasalsoexaminedbehindleadshielding(45mmthick).Thishaseventualapplicationsinthedetectionoflowconductivitymetalssuchasuranium/plutoniuminconfigurationswhichshieldagainstconventionalsignatures.InadditiontoECI,theQuSpinsensorwasalsousedtoobserveaDCcurrent(3mA)inawireshieldedbehindaluminium.Thishaspotentialapplicationswithinelectricalsafety.PicoTeslaabsolutefieldreadingswithahybrid3He/87RbmagnetometerChristopherAbel,UniversityofSussex

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GeophysicalsignalsintheELFband:0.1-50HzCiaranBeggan,BGSEdinburghTheBritishGeologicalSurveyhavebeenoperatingahigh-frequencyinductioncoilmagnetometer(100Hzcadence)attheirobservatoryinEskdalemuir(ScottishBorders)sinceJun2012.Ithasanapproximatesensitivityof0.07pTat0.1-50Hz.ThegeophysicalsignalswithinthedatasetencompasstheSchumannResonances(SR)generatedbyenergyfromequatoriallightningrefractingintheEarth-ionospherecavity,theIonosphericAlfvenResonances(IAR)oftheupperionospherecavityandmagnetosphericpulsationstriggeredbygeomagneticstorms.WecanalsoobserveseveralsubharmonicsoftheUK50Hzpowergrid.Onoccasion,locallightningstrikescanalsobeobserveddirectlyinthedata.Thesesignalsrangeinamplitudefrom0.5pTfortheIARto5pTfortheSRandupto5nTforproximallightningstorms.Inthisposter,wegiveexamplesofspectrogramsshowingeachtypeofgeophysicalsignalanddescribetheiroccurencestatisticsandtypicalamplituderanges.RecordingtheHeartBeatofCattleusingaDifferentialSystemofOpticallyPumpedMagnetometersJensUSutter1*,OliverLewis2,CliveRobinson2,AnthonyMcMahon2,RobertBoyce3,RachelBragg4,AlastairMacrae4,PaulFGriffin1,ErlingRiis1&StuartIngleby11UniversityofStrathclyde,TheDepartmentofPhysics,JohnAndersonBuilding,Glasgow,G40NG,TheScottishUniversitiesPhysicsAlliance,SUPA2PeacockTechnologyLtd.,Unit13,AlphaCentre,StirlingUniversityInnovationPark,StirlingFK94NF3IceRoboticsLtd.,Unit6SteadingBankhead,BankheadRd,SouthQueensferryEH309TF4UniversityofEdinburgh,TheRoyal(Dick)SchoolofVeterinarySciencesandTheRoslinInstitute,EasterBushCampus,MidlothianEH259RG*[email protected]%oftheEarth’shabitablesurfaceareawithaglobalvaluearound£1trillion.Thisimportanteconomicentityreliestoalargeextentonthehealthandwelfareoftheanimalsinvolved.Besideseconomicpressurethereisalsoagrowinginterestfromtheconsumerintheethicalkeepingoflivestock[Grandin2014].Theanimal’sheartrateisakeyindicatorofstressandthereforeanautomatednon-contactmeansofmeasuringheartbeatcouldenableimprovedmonitoringofanimalwelfare.Theelectricsignaloftheheartmuscleexcitationandrelaxationdoesalsocarriesamagneticfieldcomponent.Readingthemagneticfieldtoqueryheartbeatinformationavoidstheneedforcontactelectrodes.WeuseanarrayofQuSpinTotalFieldMagnetometers(QTFM®).Usingthebackgroundnoisetotime-shiftthesignalsweoptimizesignaltonoiseratioandrecordthemagneticheartsignaldownto1pTHz-1/2inthe1–20Hzfrequencyband.Usingamathematicalalgorithmweretrievetheheartrateandtheshapeofthemagneticheartexcitation.Comparisontoelectrocardiogramsshowsgoodcorrelation.

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Non-DestructiveStructuralImagingofSteelworkwithAtomicMagnetometersP.Bevington,1,2R.Gartman,1W.Chalupczak,1C.Deans,3L.Marmugi,3andF.Renzoni31NationalPhysicalLaboratory,HamptonRoad,Teddington,TW110LW,UnitedKingdom2DepartmentofPhysics,UniversityofStrathclyde,GlasgowG40NG,UnitedKingdom3DepartmentofPhysicsandAstronomy,UniversityCollegeLondon,LondonWC1E6BT,UnitedKingdomWedemonstrateimagingandtestingofthedefectsinmetallicsamplesperformedwithultrasensitiveradio-frequencyCsatomicmagnetometerinmagneticallyunscreenedenvironmentwithactivemagneticfieldcompensationsystemandameasurementgeometrysuitableforindustrialmonitoring.Weexploretheshapeandamplitudeofthespatialprofileofsignalfeaturesthatcorrespondtodefects.Bycomparingnumericalandexperimentalresultsonaseriesofbenchmarkaluminiumplateswedemonstratearobustprocessfordeterminingdefectdimensions.Wepresentdetectionofthinningofcarbonsteelplatewithasensitivityof0.1mmandproofofconceptmeasurementofstructuralevaluationofferromagneticsampleinthepresenceofconcealingconductivebarrier.BrainstimulationcombinedwithopticallypumpedmagnetometersAnnaKowalczyk,UniversityofBirmingham

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AttendeesRasmusZetter AaltoUniversityAbigailLangley AtomicWeaponsEstablishmentJoeWatson AtomicWeaponsEstablishmentOlivierMasseglia BartingtonInstrumentsCiaranBeggan BritishGeologicalSurveyMarkBrannan CambridgeConsultantsGaryKendall CDO2MattWithers CDO2JohnBurke DARPAPeterSchlosser FraunhoferCAPRahulMhaskar Geometrics,IncRobertBoyce IceRoboticsLtdVolkmarSchultze LeibnizIPHTRafalGartman NPLMichaelS.Larsen Northrop-GrummanStephenLee OptocapLtdDouglasBremner OptocapLtdReneGaio OptocapLtdAnthonyMcMahon PeacockTechnologyLtdCliveRobinson PeacockTechnologyLtdKamyarMehran QMULShwetaChoudhury QuSpin,IncVishalShah QuSpin,IncLiamWilliams RSKGroupPeterSchwindt SandiaNationalLaboratoryOleKock Teledynee2vAndrewMitchell Teledynee2vThomasW.Kornack Twinleaf,LLCSamanthaDavidson UltraElectronicsCameronDeans UCLAniaKowalczyk BirminghamUniversityMichaelTayler UniversityofCambridgeSvenjaKnappe UniversityofColoradoBenVarcoe UniversityofLeeds&CreavoMedicalTechBruceSaleeb-Mousa NottinghamUniversityDominicSims NottinghamUniversityJamesLeggett NottinghamUniversityKasperJensen NottinghamUniversityNiallHolmes NottinghamUniversityThomasFernholz NottinghamUniversityDominicHunter StrathclydeUniversityAidanArnold StrathclydeUniversityCarolynO'Dwyer StrathclydeUniversityErlingRiis StrathclydeUniversityIainChalmers StrathclydeUniversityPaulGriffin StrathclydeUniversitySimonArmstrong StrathclydeUniversityStuartIngleby StrathclydeUniversityTerryDyer StrathclydeUniversityRossJohnson StrathclydeUniversityJensSutter StrathclydeUniversityChristopherAbel UniversityofSussexMarkBason UniversityofSussexPeterKrueger UniversityofSussex