PicoQuant MultiHarp 150 - Multi-Channel Scaling

PicoQuantGmbH MultiHarpSoftwareV.3.1.0.0
5.5. Multi-Channel Scaling
IncontrasttoclassicTCSPCsystems(basedonTACs),thesyncandthesignalchannelsoftheMultiHarpare
completelyindependent.Thismakesitpossibletoallowmulti-stopmeasurements,i.e.thedetectionofmultiple
photonsbetweentwosubsequentSTARTsignals.Theshorterthedeadtimesofthedetectorsandthetiming
electronicsare,thelessthesemulti-stopmeasurementsarepronetodead-time-inducedphotonlosses.Ifthe
histogrambinwidthischosenwiderthanthedeadtime,thepile-upartifactsduetodeadtimeareentirelyelimi-
natedanditispossibletomeasureatphotonratesmuchhigherthantheclassicpile-uplimitofTCSPC.The
MultiHarpcanthenbeoperatedlikeaMulti-ChannelScaler.
Theeasiestwaytoperformmulti-channelscalingwiththeMultiHarpisviahistogrammingmode.Thedetectoris
connectedtooneoftheinputchannels.Inaddition,areferencesignalatthesyncinputmarkingthestartofthe
MCSmeasurementisneeded(seechapter8.3.1forthesignalspecifications).
Theintegrationtimeshouldthenbesettoavaluesignificantlylargerthanthetimebinwidthmultipliedbythe
numberoftimebins(65536).Thenstartameasurementininintegration(INT)mode.Theresultinghistogram
willdisplaytheMCScurve.Pleasenotethatthetimerangethatcanbeobtainedwiththismethodislimitedto
thetimebinwidthmultipliedby65536.MCSmeasurementsonlongertimerangesarepossibleviaTTTRmode.
However,thiswillrequireadditionalsoftwarefordataanalysis(e.g.,SymPhoTime64).
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