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Counting photons with an MPPC

On a sunny day (Tue, 27 Aug 2019 06:23:42 -0700 (PDT)) it happened George Herold wrote in :

Years agao I looked for SPADs and got 'we do not sell this to your country' crap.

After reading some of this here, I decided to look on ebey if they EXIST[1] now.

No S.P.A.D No single photon avalanche detector, but looked at some other entries, this caucht my attention, surprized:

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VL53L0X World smallest Time-of-Flight (ToF) ranging sensor NEW I though maybe of use for my drone's anti collision system, so started reading the desciption: .... The VL53L0X integrates a leading-edge SPAD array (Single Photon Avalanche Diodes) and embeds ST\u2019s second generation FlightSenseTM patented technology. The VL53L0X's 940nm VCSEL emitter (Vertical Cavity Surface-Emitting Laser), is totally invisible to the human eye, coupled with internal physical infrared filters, it enables longer ranging distance, higher immunity to ambient light and better robustness to cover-glass optical cross-talk. Key Features Fully integrated miniature module

940nm Laser VCSEL VCSEL driver ....

LOL, and there is the SPAD Any comments? I have ordered one just now :-) 8$26 with free shipping. ?? There is even an arduino library

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[1] Not on ebay means does not exist.
Reply to
Jan Panteltje
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The physics is completely different. Ge(Li) and IG detectors get their high resolution from the primary particle producing N carriers, where N is proportional to its energy.

MPPCs are avalanche devices, where a detection event causes the whole pixel to discharge until the avalanche stops.

Because of the highish capacitance, the output pulses aren't as symmetrical as a PMT's--the fall time is about 20x longer than the rise. So to get PMTish photon counting rates you need a more intelligent discriminator circuit that can reliably see events that arrive on the tails of other events.

Cheers

Phil Hobbs

(coming to you from beautiful Sydney BC waterfront)

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

Yup, a couple of parallelled LND150s inside the voltage feedback loop.

There's also an I2C pressure sensor to detect the chamber venting, so that we can turn off the bias and warm the device back up to 20C before we get ice all over it.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

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