need guidance in selection of photodiode for my project

I am currently working on a project to develop a fibre optic dosimetry system. The system uses an organic scintillator (BCF-60), which emits green light at 530 nm, with an active volume of 0.8 mm³.

I am in the process of designing a transimpedance amplifier (TIA) circuit using different photodetectors, which I selected based on their spectral response range (360 nm to 900 nm).

Could you please guide me on the key tests I should perform to help select the most reliable and suitable photodiode for my application?

I am planning to test the TIA response using different LEDs (blue, green, red, and IR). I would appreciate your suggestions on any additional quick and effective tests I could perform to further characterize the photodiodes for use in my dosimetry system.

In TIA cct I used Rf 100k and 741 opamp.

Kindly please guide..

Kind regards

Hasham

...

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hasamsiddiqui 1 month ago
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michaelkellett 1 month ago in reply to hasamsiddiqui

It would be hard to think of a less suitable op-amp than the 741 to use with a fancy photo-diode. (I picked one of your selection at random and noticed that it costs £17.)

Why are you biasing the photo diode with an AC source ?

I suspect that you are not equipped to measure the reliability of the photo diode - just buy from a reputable source and operate it well within ratings for reverse bias etc.

Do some reading about photo diode trans impedance amplifiers (DuckDuckGo or Google it).

Here are some starters:

https://www.ti.com/lit/pdf/tidu535

www.ti.com/.../SSZTBC4

https://www.allaboutcircuits.com/technical-articles/design-tips-for-photodiode-amplifiers/

If possible you should start by measuring the photo current coming out of your test devices before you attempt to design an amplifier of your own.

Something like this would do:

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1003

(There are other suppliers

https://www.aliexpress.com/item/1005005324917603.html

)

MK
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hasamsiddiqui 1 month ago in reply to michaelkellett

Hi,

THnaks for your reply and sharing links..

I plan to use the OPA657 op-amp, as the 741 op-amp has higher noise and is not suitable for this application.

if you don't mind, I would appreciate your guidance on how to characterize different photodiodes to help me select the most suitable one for my project.
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shabaz 1 month ago in reply to hasamsiddiqui

You've already narrowed it down to the selection you listed, so maybe just try your top two or three selections, see which one meets your needs?

What I don't understand, is you've mentioned 0.8 mm3 volume, yet from the photos, each of the selected photo diodes look large (I have not looked at their datasheets). However much light are you expecting? Is it an extremely tiny amount? If so then maybe SPADs are a better choice than photodiode? See here:

The Use of SiPMs in the Life Sciences

I could be very wrong since I'm not knowledgeable in your subject area.
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shabaz 1 month ago in reply to hasamsiddiqui

You've already narrowed it down to the selection you listed, so maybe just try your top two or three selections, see which one meets your needs?

What I don't understand, is you've mentioned 0.8 mm3 volume, yet from the photos, each of the selected photo diodes look large (I have not looked at their datasheets). However much light are you expecting? Is it an extremely tiny amount? If so then maybe SPADs are a better choice than photodiode? See here:

The Use of SiPMs in the Life Sciences

I could be very wrong since I'm not knowledgeable in your subject area.
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