Bert Pool

bpool

Fort Worth, Texas

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Julia, I know it is hard working with experiments where you are detecting single photons. Photomultipliers are just sensitive enough to do it, but dark current noise in them can be so high! I wish I had a spare avalanche diode photodetector that I could donate to your research project, to improve the signal to noise ratio you are probably dealing with on your current photomultiplier, but, alas, fate never dropped one into my hands. However, if you are interested, what I DO have is a PIN diode photon detector that's almost as good as an avalanche diode detector. I'm not currently using it, and it might work very well for your photon detection experiments. Check with your engineer and see if he/she thinks it might be of use. If so, it is yours. The specs: Analog Modules, Inc., Model 710-425 Amplifier, Ultra Low noise PIN photodiode detector, complete with 521-5 precision adjustable bias power supply Ultra low noise amplifier, 710-425, 1-10 MV/A Transimpedance Gain, Detector=FFD-100 SI PIN, Peak=900nm, Optimum bias=15V, Optical Gain=0.6-6.V/uW, Noise=5.0pW/(sqrt(Hz)) Power +-15VDC 3- mA, input photodetector, output BNC, PIN decoupled with 01.01 uF 1 kV cap. Output swing 2.5V pk(-1 and -2) or 6V pk (-3 and -4) Power supply specs: Power supply, biasing, low noise amplifier In +12V - 15V, or 24-28V DC, output +10 to +800V or -10V to -800V, using a 0 to 5 V control voltage Analog Modules, Inc., Model 521a You'd have to download the manufactures spec sheets to see if the diode's spectral response is wide enough to use with your current laser's wavelength, or perhaps instead you could use a 900 nm. laser with your double slit, as this PIN detector's sensitivity peaks at 900 nm. This unit was taken from an Alcon 193 nm Exciplex UV laser system (used for laser eye surgery - I believe the PIN photo detector was used with an IR light source and used to scan and track cornea movements.) I believe the photo detector is perfectly good, but I've never placed it in service, so it is untested, at this point. Let me know if your team is interested, and I'll ship it to you. Bert
Feb 08, 2019
Are we catching photons traveling in time?
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In the notes on the pilot study, it says the measurements were made 90 seconds after the photo multiplier was turned on. Is this because the photo multiplier being used is a vacuum tube p.m., and the 90 second wait time is for the filament and cathode to warm up and stabilize, or are you instead using a solid-state photo-avalanche or PIN diode photon sensor? I ask, because my concern is that a p.m.'s sensitivity may change over time and affect the photon counts. Not criticizing, mind you, just curious.
Feb 08, 2019
Are we catching photons traveling in time?
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