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--- howto:how_to_measure_the_instrument_response_function_irf [2023/09/07 22:49] – [How to Measure the Instrument Response Function (IRF)] peter
+++ howto:how_to_measure_the_instrument_response_function_irf [2023/09/07 22:55] (current) – [Using samples with ultrafast decay] peter
@@ Line 13: / Line 13: @@
-=== Low count rate during IRF measurements is important ===
+==== Low count rate during IRF measurements is important! ====
-**Note:**  Make sure that the detection count rate is much lower than the count rate used for fluorescence decay measurement.Diluting the scattering solution is better than using grey filters. Ideal is when the decay and the IRF are recorded at the same [[glossary:differential count rate]] (and NOT at the same average count rates).
+Make sure that the detection count rate is much lower than the count rate during a fluorescence decay measurement. Diluting the scattering solution is better than using grey (ND) filters. Ideal is when the decay and the IRF are recorded at the same [[glossary:differential count rate]] (and NOT at the same average count rate).
-If the IRF should be measured on a microscope system with SPAD detectors, in the UV range also the Raman-scattering of water can be used. E.g. the Raman scattering can be recorded with a HQ480/40 bandpass filter, if a 405nm diode is used. This method is less suited for long wavelengths, as the Raman efficiency decreases. The water must be very pure in order not to capture any fluorescence.
+If the IRF should be measured in the UV range on a microscope system with SPAD detectors, the Raman scattering of water can be used, too. E.g. the Raman scattering can be recorded with a HQ480/40 bandpass filter, if a 405nm laser diode is used. This method is less suited for long wavelengths, as the Raman scattering decreases. In order to avoid signal contamination by any fluorescence, the water must be very pure.
 ===== Using samples with ultrafast decay =====
-Some detectors (particularly SPADs) have wavelength dependent timing response. In this case an IRF recorded at the excitation wavelength may not be useful for precise reconvolution. The solution is to acquire the IRF at the fluorescence wavelength, or at least spectrally closer to the fluorescence emission.
+Some detectors (particularly MPD SPADs) have a wavelength dependent timing response. In this case an IRF recorded at the excitation wavelength may not be useful for precise reconvolution. The solution is to acquire the IRF at the fluorescence wavelength, or at least spectrally closer to the fluorescence emission wavelength.
 ==== General recipe ====