Building a photodiode radiation detector

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Күн бұрын

In this video I'm building Olliver Kellers photodiode based radiation detector.
The webside with the plans: scoollab.web.cern.ch/diy-part...

Пікірлер: 53

@oliverkeller2342 2 жыл бұрын

Thanks for covering this! I see a potential problem in your picture of the non-working alpha spectrometer build. The metal encasing of the diode is unfortunately the cathode and should not touch the metal box. Otherwise, it will make a short circuit with the electric ground (mounting holes of the PCB are grounded, intentionally). My advice would be to take a large enough metal box where the object that you want to measure an alpha spectrum from fits fully inside. Complete blocking of stray light in front of the BPX61 diode is otherwise really hard. The amplification of the alpha spectrometer circuit is several times increased compared to the electron detector, making it more susceptible to ambient light and the electromagnetic coupling of stray radiowaves (EMI).

@thesciencefurry 2 жыл бұрын

Oh hello, thx for the comment :) I'm not sure anymore but I think I made the circuit with the photodiode facing up, not touching the case aswell. Maybe I will try it again at some point. But for now I'm glad the electron detector version works. But I was wondering why I couldn't do spectroscopy, because instead of just the photodiode I had the scintillator crystal, and with that I expected to get a signal proportional of the radiation energy.

@oliverkeller2342 2 жыл бұрын

@@thesciencefurry the amplifier must fit to the diode, mine is optimized for the bpw34 and bpx61 diodes. there are different kinds of diodes which can have different characteristics. for example, silicon photomultipliers need a higher bias voltage and the specified value must be met precisely

@DaveFer Жыл бұрын

Hi Mr. Keller et al, is there a vendor that will sell me the variants of the photodiode radiation detectors pre-assembled (soldered)? I may consider incorporating them into a larger home project and I just don't have time to do all that soldering (grad school, work, hobby robotics, kids, etc).

@DaveFer Жыл бұрын

@@thesciencefurry Hey, thanks for doing this video, very very interesting. Could you tell me which lantern mantles you have that contain thorium? I would like to acquire a bunch of them. Thanks!

@ANANTHASANKAR_UA 2 жыл бұрын

I have working as Assistant professor in Electronics & Tech hobbyist...your channel is very much informative and subscribed ❤️

@klausbrandt5064 2 жыл бұрын

Excellent !!!

@pharmasolutionpakistan7668 2 жыл бұрын

good effort

@jamesluck2969 2 жыл бұрын

If anyone searching the comments would like to build a small scintillator like this but for not spectral purposes. Go on ebay you can find small square cut pieces of plastic scintillator, if your smart enough you can pair two of them together and make a cosmic detector that can subtract background for the most part. For spectral response most anything shy of plastic will work. He'll have to correct me but it looks like potentially a Tl:CsI / Na:CsI scintillator or a PbWO, all three will work and has the benefit of being fairly moisture inert

@christopherleubner6633 2 ай бұрын

CsI:Tl pairs with photodiodes well. A stupidly cheap bias is 4 to 6 CR2032 batteries. They will last years. Follow with am amplifier of your choice. My build used a j fet from a condenser microphone ❤

@CrazyLabs 9 ай бұрын

Can i conect It direct to a digital oscilloscope?

@quantumlab9130 2 жыл бұрын

I am also working on a photo diode gamma detector. Though I also looked at making an alpha one and I believe the best way to do that is to get a ZnS scintillator which can be picked up on eBay for only a few dollars. And the. Use something like aluminized Mylar (emergency blanket) for the window which allows alpha rays to pass through all while keeping light out.

@jamesluck2969 2 жыл бұрын

I'd recommend you buy the necessary mylar from someone who supplies it. iRad on Ebay sells both the mylar and Ag:ZnS screens. I believe his ebay is actually under iRad.Inc. Space blankets occasionally work for a cheap and dirty build but the coverage of the aluminum layer is pretty poor, in return more sheets need to be used. The more used the more thickness the window will have. In my exparementing without looking back at my notes the maximum window I could get away with while still detecting alpha particles was something in the range of 24um. Which is far off of what is preferred and recommended, at that point I was detecting just enough to know a source was there.

@jamesluck2969 2 жыл бұрын

Oh as a side note you could use super high polished acrylic as your light guide, or even plain glass to produce something with more surface area than just the photo detector head

@quantumlab9130 2 жыл бұрын

Indeed, Irad on eBay does sell everything required. And his Mylar windows are much better than a space blanket.

@christopherleubner6633 2 ай бұрын

Get a bigger pin type photodiode, then remove the window from it.

@16BITMEME 2 жыл бұрын

Can i use a photo transistor?

@Neptunium 9 ай бұрын

Very cool channel! I have been looking for this device but the website does not seem to be updated.. I sent an email to the info link.. thanks for putting it together! great channel! Subscribed!

@Draauz 2 жыл бұрын

sick

@mikemullenix6956 4 ай бұрын

Thanks for building this , now can you build its brother the alfa detector?

@klausbrandt5064 2 жыл бұрын

I love your videos, please can you do more fm transmitter projects ?

@thesciencefurry 2 жыл бұрын

Currently I have a lot of other stuff planned, but I'll get back to that eventually.

@klausbrandt5064 2 жыл бұрын

@@thesciencefurry that would be great. Thankyou very much

@blsemetan7232 11 ай бұрын

Looks mostly like an OP amp with a photodiode... one could modify a AM FM radio amp circuit, throw in a photodiode, switch etc.. AM FM Radio with Radiation Detector lol.

@PedroHenrique-xm1yt Ай бұрын

Hi :) i made a similar project, polishing a bpw34 for alpha detection. Im still waiting for my usb sound card, but so far, theres an insanely loud 60hz buzz whem plugging it to my motherboard 3.5mm jack. Do you think it's impossible to get rid of it? I can't use it on my computer, i can only use it on my laptop without the charger plugged :/ if i charge it, i get the same 60hz hum

@thesciencefurry Ай бұрын

Seems to be the laptop/charger If you shielded everything on your device idk what you could do🤔

@PedroHenrique-xm1yt Ай бұрын

@@thesciencefurry I was just using a plastic box, now I wrapped it in aluminum foil (I don't have a metal box with me right now) and it appears to have solved it :)

@MrEdwinHubble 2 жыл бұрын

Hi! I have been experimenting with the same exact diode + CdWO scintillator combination. The electrical setup is very similar, however it is based on an op amp of 60MHz bandwith. But I have a hunch that the penetrating gamma and beta particles trigger the photodiode. Instead of the light created by the scintillator. How am I sure about this? Well, the count rate is very low. At least it should be 5-8 counts per second! Since the scintillator has a lot of volume to produce individual flashes. I think the detector with the current diode could be improved with a reverse biasing of 12 or 14 volts. As far as I know in my and your setup as well it has some bias but not very much.

@thesciencefurry 2 жыл бұрын

This is true. I detached the scintillator at some point and it had the sane count rate with just the photodiode.

@MrEdwinHubble 2 жыл бұрын

@@thesciencefurry Hmm, then that concludes. I think if the diode is reverse biased highly enough ( i contacted the scintillator/diode selller earlier and he said that the diode can withstand around 30V reverse bias) then the gain will be better and individual light flashes could be detected. At the physics-open-lab you can find an article where the author used a standard PIN diode and a NaI scintillator. However the charge sensitive amplifier had a 1Gohm feedback resistor instead of the 40Megaohm which is used in this circuit. I did a cross check and it had roughly the same count rate with a BPW34 diode too (without scintillator). So i think the next step is to reverse bias the PIN diode with about 20-24V and de-couple the output with a few nF SMT capacitor.

@MrEdwinHubble 2 жыл бұрын

@@thesciencefurry Also, how did you manage to detach the diode from the scintillator? CdWO4 is toxic stuff. Did you use some sort of solvent?

@thesciencefurry 2 жыл бұрын

@@MrEdwinHubble No I wiggled it around until it came loose😅

@MrEdwinHubble 2 жыл бұрын

@@thesciencefurry I wonder if it was just held there with a commercial glue and not with an optical binding agent... Well, the CdWO scintillator will come in handy tho. Do you have experience with plastic scintillators in gamma spectroscopy? I heard it is unsuitable for such measurements, but some studies prove otherwise.

@johneagle4384 2 жыл бұрын

Is it possibe to purchase the complete kit?

@thesciencefurry 2 жыл бұрын

Not that I know of.

@AmaroqStarwind Жыл бұрын

But can you make a radiation detector for a gameboy?

@omsingharjit Жыл бұрын

So scintillator is needed ??

@thesciencefurry Жыл бұрын

No, I actually detached the scintillator from the photodiode and it performrd the same.

@omsingharjit Жыл бұрын

@@thesciencefurry if it's so useful than why photo multiplayer is used instead of photodiodes ? and will it also detect soft and hard x ?

@thesciencefurry Жыл бұрын

@@omsingharjit A photomultiplier needs a different amplifier circuit. I wanted to build a gamma spectrometer but it's pretty expensive

@omsingharjit Жыл бұрын

@@thesciencefurry no , I asked something else by the way .. have you successfully made Gamma spectroscopy meter using Photo sensor ?

@thesciencefurry Жыл бұрын

@@omsingharjit Ah, the photomultipier is way more sensitive. It can detect single photons. And no I haven't got it to work. You can do alpha spectroscopy with the other circuit. But I never got it to work.

@nakulchadda6384 2 жыл бұрын

what do u do as a job

@thesciencefurry 2 жыл бұрын

I'm a lab tech apprentice

@frostedlambs 2 жыл бұрын

Maybe the alpha particles are getting blocked as they can be easily stopped by paper

@thesciencefurry 2 жыл бұрын

No that's just a generalisation. It can penetrate Paper.

@jamesluck2969 2 жыл бұрын

@@thesciencefurry I'm finally glad someone else has said it. Most alpha particles will be stopped by paper but not all, and after a long enough duration super small holes will be punched letting more in. The most mylar I've put infront of a detector and still detected a response was something like 24-36um, I'll have to look back at my notes.