SiPM/MPPC Questions & Answers

What’s an MPPC? Is it similar to an SiPM?

MPPC stands for Multi-Pixel Photon Counter, the product family that includes our SiPMs. Since we believe the future of Geiger-mode gain detectors includes more than just silicon-based devices, we’ve adopted the term MPPC to cover all the various materials (like InGaAs) that can be used to catch those shifty little photons!

What’s the maximum amount of light that I can put into my MPPC, photodiode, or APD?

If your detector is or has the potential to be exposed to strong light, try to keep the detector’s average current below 100 mA. The detector will be non-linear well before this current range, and exceeding it may cause damage—especially in devices with a wirebond connection. While the detector won’t explode or disintegrate (well, maybe disintegrate if it’s reaaaaalllyyy strong laser light), the wirebond will disconnect and create an open circuit. This destroys a detector’s ability to send current outside of its package.

How do I know which MPPC or SiPM microcell size to pick?

The microcell size affects a few parameters of the MPPC. As you probably know, each microcell requires a quenching resistor which takes up a portion of each microcell’s area, reducing the fill factor. The quenching resistor takes up a smaller percentage of the microcell area as the microcell sizes become larger and larger, so larger microcells have higher fill factor and subsequently higher photon detection efficiency (PDE).

However, larger microcells also mean there are less microcells per unit area. Since the upper limit of an MPPC’s linearity is determined by the number of available microcells, then MPPCs with larger microcells will have a lower upper limit or linearity than an identical-sized MPPC with smaller microcells.

There are other factors to consider as well; for example, larger microcells have larger gain but slower time response due to higher capacitance. Dark counts are pretty much identical, but crosstalk may be higher with larger microcells.

How big of an MPPC array can I get?

Our largest off-the-shelf array is 4x4ch 6mm sq. MPPC array or 8x8ch 3mm sq. MPPC array. We can also offer custom-size arrays or the individual tile-able package MPPC, so the customer can create an array of their own size or shape.

If you’ve got a technical question you’d like to see answered on this page, email us.

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Meet the engineers

Dino Butron is an Applications Engineer, specializing in all of our point detectors and signal-to-noise simulations. He and his photonic sidekick (his cat Bash) tackle technical issues daily.

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