Fluoromax-4在近红外区的拓展

Introduction When the benchtop FluoroMax-4 spectrofluorometer is fitted with ourstandard Hamamatsu R928Pphotomultiplier tube， the performance ofthis detector rapidly drops above 800nm. With the rapid rise of nanoparticleand quantum-dot research in a variety ofscientific fields， however， thereisagrowing interest in fluorescencemeasurements further into the near-IR. The main problem withphotomultiplier tubes as we venture intolonger wavelengthsisspontaneousemission from the photocathode， whichincreases the dark noise. This is whythe R928P， for example， has a higherdark-noise background， than， say， theHamamatsu R1527， which is often usedto demonstrate a high signal-to-noiseratio， though it is poor at detectingsignals with wavelengths longer than600 nm. The answer is to cool thedetectors as much as possible， thuslowering the dark noise， though this alsoaffects their range. If maximum dark-noise reductionIS； required，a，tlhe modular Fluorologsystem is the obvious choice， becausesome of the most exotic detectors canbe adapted to this modularconfiguration. How，though， cann vweincrease the range of the FluoroMaxinto the near-IR? To test ttheFluoroMaxs response， we modified theFluoroMax， and inside mountedaHamamatsu R2658P， which has a rangeextending just beyond 1000 nm， andcompared it to the R928P. Near-IR performance comparison Fig. 1 compares the spectra of alaser glass sample we normallyuse forIR calibration， run in a FluoroMax@-4with a standard R928P and then anR2658P. Excitation was at 530 nm， with5 nm excitation bandpass and 8 nmemission bandpass.Integration timewas 0.1 s. A 550 nm long-pass filterremoved stray excitation light. Spectrawere corrected for dark noise. Note that thee R928P stilldominates in sensitivity out toapproximately 850 nm. Beyond 850 nmtheR928Pplummetsprecipitously，while the R2658 dominates. In fact， by900 nm， the quantum efficiency of theR928P is virtually zero. The R2658 alsoalsogivessurprisingly respectableperformance throughout the visible andUV， as shown in a comparison of thestandard sensitivity test of water Ramanspectra (Fig. 2) in a FluoroMax-4.Excitation was at 350 nm with 5 nmexcitation and emissioni bandpassesand 0.1 s integration time. Conclusions If the region from 850 nm to 1010nm is important to your work， then theR2658 is an indispensable detector. Awater Raman spectrum with the R2658yieldsapeakintensitoyf ofalmost150 000 counts/s， which is still betterthan almost any other spectrofluoro-meter-except a standard FluoroMaxor Fluorolog. Wavelength (nm) Fig. 1. Comparison of spectra from a laser glass taken with R928 and R2658 photomultiplier tubes in aFluoroMax -4. 入exc=530 nm； bandpass=5 nm excitation and 8 nm emission； integration time = 0.1 s；550 nm long-pass filter on emission； correction for dark noise. Wavelength (nm) Fig. 2. Water-Raman spectral comparison between R928 and R2658 photomultiplier tubes in a Fluoro-Max -4. water Raman peak. Integration time=0.1 s； 入exc=350 nm； all bandpasses =5 nm； high voltagefor R928= 950 V；high voltage for R2658=1500 V. ( USA： H ORIBA Jobin Yvon In c .， 3 8 80 Park Avenue， Edison， NJ 08 8 20-3012， Toll-Free：+1 - 866-jobinyvon Tel：+1-732-494-8660， Fax：+1-732-549-5125， E-mail ： info@jobinyvon.com，www.jobinyvon.com France： H ORIBA Jobin Yvon S . A . S.， 1 6-18， rue du Canal ， 9116 5 Longjumeau Cedex， ) ( T el： + 33 (0) 1 64 54 13 00， F ax： +33 (0) 169 09 93 1 9， www.jobinyvon. f r Japan： H ORIBA Ltd.， JY O p tical Sales Dept， H i g ashi-Kanda，D a iji B uilding， 1-7-8 Higashi-Kanda ) ( Chiyoda-ku， T okyo 1 0 1-0031， T e l： +81 (0) 3 3861 8231， www.jyhoriba.jp Germany： +49(0)89462317-0 I taly： +3902 57603050 U K： +44 (0) 20 8204 8142 ) Copyright C HORIBA Jobin Yvon； version .HORIBAExplore the future HORIBAJOBIN YVONChina： + ORIBAExplore the future