FiTS:Fibre TransmissionSystem

Overview

• Maunakea SpectroscopicExplorer(MSE)– Background– Sciencegoals

• FiTS:TheFibre TransmissionSystem– Requirements– DesignandAnalysis– StatusandFutureWork

• TheUVic Fibre TestFacility– Goalsofthefacility– UVic /FTOTeam

• Conclusions

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• Widefield,highlymultiplexedspectroscopicfacilitiesareurgentlyneeded,especiallytocomplementwidefieldimagingfacilities

• Itisrelativelystraightforwardtoupgrade3.6mCFHTtoawidefield11mtelescopeinexistingbuildingonMaunaKea(ina“dome”withalargeraperture)

• FormalconceptualdesignstudyhasjustbeencompletedbyinternationalpartnershipthatincludesCanada,France,Hawaii,China,India,Australia,Spain

• http://mse.cfht.hawaii.edu/

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BackgroundonMSE

• TheUniverseiscomposedofDarkMatterandDarkEnergybothofwhicharechallengingforobservations

• DarkMatterperhapsbestexploredbystudyingverylargesamplesofstarsintheMilkyWay

• DarkEnergyperhapsbestexploredbystudyingverylargesamplesofgalaxiesatdifferentdistancesoverthewholesky

• =>Needprecisionspectroscopyoftenstohundredsofmillionsoffaintstarsandgalaxiesoverwholesky

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BIGSciencequestions

WMAP9yr

SeeMSEDetailedSciencecase:http://mse.cfht.hawaii.edu/science/mse-science-docs/DSC/MSE_DSC_ExpDraft_27May2016.pdf

• Fainttargets=>largecollectingarea,veryefficientopticalsystem• Largearea=>largefield(effectivelylimitedbyphysicalsizesoflenses)• Typicaltargetdensities=>thousandsofspectra• Targetselection=>fibersareonlypracticalsolution• Precisionspectroscopyrequiresextremelywellcharacterized,stablespectra

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SciencetoRequirements

Therefore,MSEtop-levelrequirementsare:• Telescope:11maperture,1.5sq.deg field• Wavelengthrange:0.37– 1.8um• >3200low/mediumresolutionspectra,>1000highresspectraperfield• SpectralresolutionfromR=2,500toR=40,000• Sensitivity:24magnitudeobjects(@SNR=2)• Spectro-photometricaccuracy<3%• Velocityprecisionof20km/s(@SNR=5)

• SciencerequirementsflowdownintokeyFiTS requirements– Throughput

• >90%@900nm(HRfibres)• >85%@900nm(LMRfibres)

– FocalRatioDegradation(FRD)<5%– Spectralandphotometricstability

• RequirementsstillTBD

• Howeverfibertransportusually producessignificantlightlosses,variabletransmissionandvariableimagequality– NeedtopaycarefulattentiontodetailsofdesignofFiTS,including

extensivetestingofalloptionsandcomponents

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FiTS Requirements

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FiTS Design

Fibre opticcablescarrylightfromMSEprime-focus…

To2High-ResolutionSpectrographs…

and6Low/Med-ResolutionSpectrographs(inthelowerCoudé room)

Distance:35mtoHR50mtoLMR

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FiTS Design

MSETop-EndAssembly(primefocus)

Fibre positioningsystem(suppliedbyothers)• Individuallypositions4332fibres w/infield• De-rotatesfieldmotionduringobservation

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CableDesignandAnalysis

• WorkingwithFibreTech Optica todevelopmodularfibre cables

• NeedhighthroughputfibrematerialsandexcellentARcoatings,overaverybroadwavelengthrange

• PreparingforDelta-CoDR inlatewinter/earlyspring• Currentlyworkingtofullydefinerequirements• Projectstillneeds:

– Betterdefinitionofintegrationandtestsequencewiththepositioningsystemandtelescope

– Aplanforaddressingstabilityrequirements,throughmodellingortesting– Researchintocandidatefibre materials– ResearchintobroadbandARcoatingsforfibres

• Projectwillbeamulti-milliondollareffort– Testingofsomanyfibres istimeconsumingandexpensive

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StatusandFutureWork

• CurrentlybeingbuiltinDr.ColinBradley’slabwithintheDepartmentofMechanicalEngineering

• BeganconstructioninNovemberfollowingavisittoFiberTech Optica(FTO)bytwoteammembers(seeposter!)

• Plannedtestsinclude:• Ringtest

• explorefibre focalratiodegradation(FRD),aimingtoverifytheFRD< 5%requirement

• Formedbeamtest• studytheeffectsoffibre cladding,joiningproceduresanddynamics

onFRD(simulatingon-skyconditions)• Multi-fibre behaviour,cross-talkandthroughput• Testautomation

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UVicFiTSFacility

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SchematicoftheFormedBeamTest

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UVicFiTSFacilityII

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SchematicoftheRingTest

• StephanieMonty(BScstudent,Astronomy)– Managingproject,responsibleforrequirementsdefinition

• FarbodJahandar(MScstudent,Astronomy)andCollinKielty(PhDstudent,Astronomy)– Softwaredevelopment,imageprocessingandmotioncontrol

• Jooyoung Lee(MASc student,Mech Engineering)– Opto-mechanicaldesign,hardwaredevelopment

• SupervisionfromDr.KimVenn(PhysicsandAstronomy)andDr.ColinBradley(Mech Engineering)

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UVICTeam

• MSEisanexcitingproject,addressingtheneedforhighly-multiplexed,wide-fieldspectroscopy

• FiTS Fibre TransmissionSystemisanintegralpartofthefacilitydesign– Requirementsandscaleofprojectarechallenging

• Challengesexistinthedesign,constructionandtesting• KeystosuccessareastrongpartnershipbetweenNRC-H,FTO

andUVic,leveragingthecapabilitiesofeachorganization

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Conclusions