简介：Neutronusuallyappearswithgamma,whichisrequiringthedetectorhasthecapabilityofngammadiscrimination.Pulseshapediscrimination(PSD)isacommonapproachofn,gammajudgment,butrequiredacomplexprocesstoselectasuitablediscriminationfactor,andpoorperformanceinthelowenergyrange.AmethodbasedonthetimeintervalofadjacentSignalswasdisruptedandadoptedtocomparetopulseshapediscriminationinthefastneutrondetectionmethod.AgoodagreementbetweentheadoptedmethodandPSDmethodwasachieved,includingthetotalcountratioandneutroncountratio.Thecomparisonprovesthecorrectnessofthetheoreticalderivationandvalidatesthemethodinpractice.TheadvantagesandlimitationsofthemethodbasedontimeIntervalofadjacentsignalswereanalyzed.Themethodprovidesaneffectivewaytoconfirmthecalibrationoftheneutrondetectionofaliquidscintillationdetector.Also,asasimplewayonlyrequiringthetimeinformationaboutevents,thedescribedmethodhaslargeapplicationpotentialinsomecaseoffastneutronfluxorintensitymeasurement.

简介：Adischarge-produced-plasma(DPP)sourceemittingintheextremeultraviolet(EUV)spectralregionisrunningattheENEAFrascatiResearchCentre.Theplasmaisgeneratedinlow-pressurexenongasandefficientlyemits100-nsdurationradiationpulsesinthe10–20-nmwavelengthrange,withanenergyof20mJ/shot/srata10-Hzrepetitionrate.Thecomplexdischargeevolutionisconstantlyexaminedandcontrolledwithelectricalmeasurements,whileansgatedCCDcameraallowedobservationofthedischargedevelopmentinthevisible,detectionoftime-resolvedplasmacolumnpinching,andoptimizationofthepre-ionizationtiming.AccuratelycalibratedZr-filteredPINdiodesareusedtomonitorthetemporalbehaviourandenergyemissionoftheEUVpulses,whilethecalibrationofadosimetricfilmallowsquantitativeimagingoftheemittedradiation.Thiscomprehensiveplasmadiagnosticshasdemonstrateditseffectivenessinsuitablyadjustingthesourceconfigurationforseveralapplications,suchasexposuresofphotonicmaterialsandinnovativephotoresists.

简介：Broadband（1.6–18THz）terahertztime-domainspectroscopy（THz-TDS）andtime-resolvedterahertzspectroscopy（TRTS）wereperformedona54μmthickchalcogenideglass(As30Se30Te40)samplewithatwo-colorlaser-inducedairplasmaTHzsystemintransmissionandreflectionmodes,respectively.Twoabsorptionbandsat2–3and5–8THzwereobserved.TRTSrevealsanultrafastrelaxationprocessofthephotoinducedcarrierresponse,welldescribedbyarateequationmodelwithafiniteconcentrationofmid-bandgaptrapstatesforself-trappedexcitons.ThephotoinducedconductivitycanbewelldescribedbytheDrude–Smithconductivitymodelwithacarrierscatteringtimeof12–17fs,andweobservesignificantcarrierlocalizationeffects.Afastrefractiveindexchangewasobserved100fsbeforetheconductivityreacheditsmaximum,with2ordersofmagnitudelargeramplitudethanexpectedfortheopticallyinducedTHzKerreffect,indicatingthatfreecarriersareresponsibleforthetransientindexchange.

简介：ByusinganewgenerallyprojectiveRiccatiequationmethodandwiththehelpofsymboliccomputation,weconsideranonlinearGross-Pitaevskiiequationwithweakbiasmagneticandtime-dependentlaserfields.Asaresult,somenewsolitonsolutions,rationalfunctionsolution,andperiodicsolutionsareobtained.

简介：BasedonageneralanalysisofGreenfunctionsinthereal-timethermalfieldtheory,wehaveproventhatthefour-pointamputatedfunctionsinanNJLmodelinthefermionbubblediagramapproximationbehavelikeusualtwo-pointfunctions.WeexpoundthethermaltransformationsofthematrixpropagatorsforascalarboundstateintheFFbasisandintheRAbasisrespectively.Theresultingphysicalcausal,advancedandretardedpropagatorsarerespectivelyidenticaltocorrespondingonesderivedintheimaginary-timeformalism,andthisshowsonceagainthecompleteequivalenceofthetwoformalismsofthermalfieldtheoryonthediscussedproblemintheNJLmodel.

简介：Thegroup-delaydispersionofanopticalfiberwasmeasuredwiththetime-of-flightmethod,usingfingerprint-likecharacteristicspectrafromamode-lockedfiberlasersource.Todeterminethegroup-delaydispersionuptothefourthorder,least-squaresfittingwasappliedtotheoveralltimewaveformmappedonthetimeaxisforthefingerprint-spectralbroadbandpulsesthroughalongopticalfiber.Theanalysisofall4003datapointsreducedstatisticaluncertainty,andprovidedsecond-,third-,andfourth-orderdispersionwithuncertaintiesof0.02%,0.4%,and4%,respectively.

简介：Wedemonstratethatthemethodologyoffrequency-resolvedopticalgating(FROG)isapplicabletotime-resolvedreflectionspectroscopyofaplasmamirrorinthevacuum-ultraviolet(VUV)region.Ourrecentstudy[R.Itakuraetal.Opt.Express23,10914(2015)]hasshownthataVUVwaveformcanberetrievedfromaVUVreflectionspectrogramofaplasmamirrorformedonafusedsilica(FS)surfacebyirradiationwithanintensefemtosecondlaserpulse.Simultaneously,theincreaseinthereflectivitywithrespecttotheFresnelreflectionoftheunexcitedFSsurfacecanbeobtainedasatime-dependentreflectivityoftheplasmamirror.Inthisstudy,weupdatetheFROGanalysisprocedureusingtheleast-squaregeneralizedprojectionsalgorithm.Thisprocedurecanreachconvergencemuchfasterthanthepreviousoneandhasnoaliasingproblem.ItisdemonstratedthatasignificantlychirpedVUVpulseaslongas1pscanbepreciselycharacterized.

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简介：Afullycoherentfreeelectronlaser(FEL)seededwithahigher-orderharmonic(HH)pulsefromhigh-orderharmonicgeneration(HHG)issuccessfullyoperatedforasufficientlyprolongedtimeinpilotuserexperimentsbyusingatimingdriftfeedback.ForHHG-seededFELs,theseedinglaserpulseshavetobesynchronizedwithelectronbunches.DespiteseededFELsbeingnon-chaoticlightsourcesinprinciple,externallaser-seededFELsareoftenunstableinpracticebecauseofatimingjitterandadriftbetweentheseedinglaserpulsesandtheacceleratedelectronbunches.Accordingly,weconstructedarelativearrival-timingmonitorbasedonnon-invasiveelectro-opticsampling(EOS).TheEOSmonitormadeuninterruptedshot-to-shotmonitoringpossibleevenduringtheseededFELoperation.TheEOSsystemwasthenusedforarrival-timingfeedbackwithanadjustabilityof100fsforcontinualoperationoftheHHG-seededFEL.UsingtheEOS-basedbeamdriftcontrollingsystem,theHHG-seededFELwasoperatedoverhalfadaywithaneffectivehitrateof20%–30%.Theoutputpulseenergywas20μJatthe61.2nmwavelength.TowardsseededFELsinthewaterwindowregion,weinvestigatedourupgradeplantoseedhigh-powerFELswithHHphotonenergyof30–100eVandlaseatshorterwavelengthsofupto2nmthroughhigh-gainharmonicgeneration(HGHG)attheenergy-upgradedSPring-8CompactSASESource(SCSS)accelerator.WestudiedabenefitaswellasthefeasibilityofthenextHHG-seededFELmachinewithsingle-stageHGHGwithtunabilityofalasingwavelength.

简介：TypeIX-rayburstsarethemostfrequentthermonuclearexplosionsinnature,resultingfromthermonuclearrunawayonthesurfaceofanaccretingneutronstar[1].Thebreakoutreaction14O(α,p)17FfromthehotCNOcyclemayhaveaprominentimpactontheburstlightcurveandburstashes[2].However,insufficientexperimentalinformationisavailabletocalculateareliable,preciserateforthisreaction[3].Weproposedtoaddresstheexperimentalinvestigationofthe14O(α,p)17FusingTimeProjectionChamber(TPC)[4].