PicoQuant MultiHarp 150 - Using TTTR Mode Data Files; TTTR Mode Measurements with Real-Time Correlation

PicoQuantGmbH MultiHarpSoftwareV.3.1.0.0
subdividingthescanlinesintime.Theaccuracyofmarkertimingisontheorderof50ns.Note,however,thatin
T3modeitcanneverberesolvedbetterthanonesyncperiod.
Aprogrammablemarkerhold-offtimecanbeusedtosuppressglitchesonthemarkersignalsthatsomepoorly
designedscanhardwareorcablereflectionsmightcreate.Theideaisthatwhenamarkersignalwasdetected
thenext(spurious)markerwillbesuppressedifitoccurswithinthehold-offtimeafterthefirstdetection.The
hold-offtimecanbechoseninthesoftwaresettingsdialogavailablethroughtheToolbar.
5.3.6. Using TTTR Mode Data Files
FordiagnosticpurposesyoumayreloadaT3modefileintotheMultiHarpsoftware.Thelimitationisthatyouwill
onlybeabletoformahistogramoverthestart-stoptimesinyourT3modedata.Thetime-taginformationwill
notbeusedhere.TheMultiHarpsoftwarewillrecognizethatyouareloadingaT3modefileandhowmany
recordsarecontainedinit.Itwillthenpromptyouforarangetouseforhistogramming.Thehistogramwillgoto
blocks0..N-1ofthehistogrammemorywhereNisthenumberofchannelsthatwereusedintheT3modemea-
surement.ATTTRmodefilealsocontainsallcontrolpanelsettingsthatwereactiveatthetimeofthemeasure-
mentrun.AfterloadingaTTTRmodefile,youwillfindthedocumenttitlereading“Histogramfrom...”.Ifyou
choosetosavesuchdatayouwillhavetogiveitanewfilename(*.phu). Thisisbecausenowahistogram
hasbeenformed,andsavingitwiththesamefilenamewoulddestroytheoriginalTTTRmodefile. However,
youmaysavethepreviouslyformedhistogramasifitwereobtainedinnormalinteractivemode,toastandard
MultiHarphistogramdatafile(*.phu).
ReloadingT3modefilesservesasaquickdiagnostictoolonly.ForT2modefilessuchafeatureiscurrentlynot
available.FurtherprocessingoranalysisofTTTRmodedatamustthereforebeperformedthroughexternaldata
analysissoftware.SuchsoftwareisavailablefromPicoQuantforawiderangeofanalysistasks(undertheprod-
uctnamesSymPhoTimeandQuCoa).Furtherspecializedanalysiscanbeperformedbydedicatedcustomsoft-
ware.IfyouwishtosavethecostforthecommercialTTTRanalysissoftwareorifyourequirespecialanalysis
algorithmsyoumaywanttoprogramyourownanalysissoftware.Fordevelopmentofyourowncustompro-
grams,pleaserefertothedemocodeforloading.phuand.ptufiles.Demosourcecodeisincludedonyour
MultiHarpinstallationmediaandwillbeinstalledbythesoftwaresetupintothesubfolderfiledemo.Alsosee
section8.2forthefileformatspecifications.Theparagraphbelowgivesonlyanoutline.
ThefirstpartofaTTTRmodefileisaheaderwiththebasicsetupinformation,similartothatoftheother
modes.Whatfollowsaftertheheaderisasequenceof32bitTTTRrecords.TheTTTRrecordsinthefilecon-
sistofdifferentpiecesofinformationingroupsofbits.Thesepiecesofinformationmustbeextractedbyabit
masking/shiftingoperation.TheirspecificlayoutisdifferentforT2andT3mode.Inbothcases,inadditionto
extractingthebitfields,thesoftwaremuststepthroughthewholefileandinterprettheoverflowrecordsandcor-
recttheoveralltimeaxisaccordingly.Detailsonhowthiscanbedoneshouldbelookedupinthedemopro-
gramsthatareinstalledaspartofthesoftwaredistribution.
5.3.7. TTTR Mode Measurements with Real–Time Correlation
AnimportantapplicationoftheMultiHarpanditsTTTRmodeisFluorescenceCorrelationSpectroscopy(FCS).
WhileTTTRdatacollectionandoff–linesoftwarecorrelationhasbeenusedforquitesometime,PCshaveonly
recentlybecomefastenoughtocalculatethecorrelationfunction“onthefly”whilethedataisbeingcollected.
ThiscapabilitycanbeveryusefulinsettingupandmonitoringFCSexperiments.TheMultiHarpsoftwarepro-
videssuchareal–timesoftwarecorrelatorforT2andT3mode.Notethatthisisnotacorrelatorforg
(2)
correla-
tionscommoninquantumoptics.IfyouneedthistypeofcorrelatorpleaseconsiderPicoQuant’sQuCoasoft-
ware.
AlthoughitcollectsthesametypeofdataasregularTTTRmode,thereal–timecorrelatorhas
itsownbuttonontheToolbar.
ThenextfigureshowstheTTTRmodecorrelatordialog.
Thelowersectionofthedialogprovidesthesamefilehandlingandprogressindicatorelementsasinregular
TTTRmode.Pleaserefertosection5.3fordetails.Theuppersectionofthedialogcontainsthecorrelatordis-
playandvariouscontrolelements.ThedialogsectionCor(Ax,Bx)allowstoselectindividualinputchannelsfor
thecorrelation.Notethatthisislimitedto16channels,evenwhenthehardwarehasmoreinputchannels.Aand
Barethevirtualinputchannelstobecorrelated.AllphysicalinputchannelsthataretickedincolumnsAandB,
respectively,willbeaggregatedandusedinthecorrespondingcorrelationchannel.Ifyourselectionisempty,
theheadingofthesectionCor(Ax,Bx)willturnredtoindicatetheproblem.Ifyouproceedanywayyouwillget
errormessagesuponstart.
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