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SiPin Photodiode Matrix

A project log for Cosmic Array

An array of individual cosmic ray detectors distributed across a landscape to display how cosmic rays arrive as showers of muons.

Robert Hart 04/08/2017 at 22:513 Comments

To get the price of each cosmic ray detector in the array down, I am currently developing a solid state detector using a matrix of low cost BPW34F SiPin Photodiodes, without the use of a scintillation panel. I have already used these diodes in other experiments and although on there own there are many limitations in it maybe possible to overcome them in a larger matrix.
https://hackaday.io/project/1749-solid-state-ionising-radiation-detector

The aim of this design will be to use layers of individually amplified photodiodes in a matrix where each matrix element is strongly pulse shaped. Coincidence detection is then measured between layers to identify relative location of where a Muon has passed through to produce each a colour and musical note output. This is a similar, but not identical method to the on used in my Cosmic Ray Hodoscope detector using GM tubes, but on a much smaller scale:
https://hackaday.io/project/1700-cosmic-ray-muon-81-9x9-pixel-hodoscope

Discussions

peter jansen wrote 04/09/2017 at 03:53 point

This is a really interesting project.  I'm not sure if this would be of help, but I built some relatively inexpensive (I think around $30?) and easily assembled detectors using stacks of BPW34s ( https://hackaday.io/project/5946/log/20074-assembling-and-characterizing-the-modular-detector-rev1 ).  I think the most expensive bit was the first-stage amplifier, and if this was replaced with something less fancy the BOM could likely be reduced significantly.  The Radiation Watch Type 5 detectors are also about double the price (in the $70 range in single-quantity), but use a much larger photodiode (about 10x10mm) intended for radiation detection, and they seem to work very well -- though of course both of those options still get expensive at scale. 

I really need to find resources to better understand how pulse shaping can be used to better determine energy level out of these sensors.  

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Robert Hart wrote 04/09/2017 at 08:40 point

Yes I know this circuit, (nice work) I've had a google search alert going for some years now and currently have several designs using the BPW34 but in this detector I need a larger aperture as the count rate for muons is very low. so I'll need at least 2 layers of 8 BPW34 but still able to tease out a pulse from each.

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Robert Hart wrote 04/09/2017 at 08:43 point

I really need to knuckle down an build a few PCB prototype configurations. Being all SMD its to hard prototype without making a number of PCBs

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