CONTENTS Emission Measurements Samples Preparation Fluorescence spectra Difficulties and limits...
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Transcript of CONTENTS Emission Measurements Samples Preparation Fluorescence spectra Difficulties and limits...
NASIR KHAN
SBL Meeting 2014, Nov 21st
Measurement of Primary Emission Spectrum of Mixed LS
CONTENTS
• Emission Measurements
• Samples Preparation
• Fluorescence spectra
• Difficulties and limits
• Results and conclusions
• APPARATUS– Agilent Technology Cary Eclipse Spectrophotometer
• METHODS
EMISSION MEASUREMENTS
– Diluted PPO in Cyclohexane.
– Diluted bisMSB in Cyclohexane.
– LAB-LS (3g/L PPO + 30mg/L bisMSB)
– Ultima Gold-F (UGF)
– UGF-LS (LAB-LS + UG-F in 9:1 by weight)
SAMPLE PREPARATION
PPO Back Face samples excited at 300nm• Different concentrations• Low concentration gives the expected primary emission using Back Face geometry • More concentration; more stokes shift• Self absorption
PPO Front Face
Concentration makes small difference
PPO Front Face & Back FaceEven concentrated sample gave primary spectrum
bisMSB Front Face & Back Face
Method makes valuable changes
LAB-LS Front Face and Back Face We expect Front Face LAB-LS should show spectrum of PPO as primary emission, But it does not show, as the light can be absorbed by bisMSB also.Front Face of a liquid gives detail of its constituents depending upon the excitation range, LAB-LS shows all components.
Continue.…Using the same Front Face method we tried to find the primary emission of Ultima Gold-F.But unfortunately we found no fruitful results as we don’t know its constituents.
UGF
Back Face
Front Face
LS-UGFGreen, Back Face, will reach to detector.
CONCLUSION Method
– Self-absorption & Re-emission problem in Back Face setup.
– Front Face geometry adopted.
– We expect primary emission of LAB-LS will be more like PPO.
Spectroscopy
– We can not find Primary emission of LAB-LS or bisMSB or UG-F with
photo spectrometer.
– Using X-Ray spectroscopy we may find primary emission of LAB-LS
and may also of Ultima Gold-F.
Thank you forattention….!
bisMSB Back Face Excited at 340nm
– Low concentration is giving the expected Primary emission.– High concentration shows stoke shift.
Front Face bisMSB Different concentration = same expected Emission.