In the last year or two we've been doing a lot of work aimed at replacing photomultiplier tubes (PMTs) in instruments, using avalanche photodiodes (APDs) and silicon photomultipliers (SiPMs). These devices are arrays of single-photon detectors, so they're also known as multi-pixel photon counters (MPPCs). Our main application areas include biomedical instruments such as flow cytometers and microplate readers, which have to measure low light levels very precisely but don't need the ultralow dark current of PMTs. (Follow-on articles will talk about our SiPM work in airborne lidar and SEM cathodoluminescence, as well as on improving the performance of actual PMTs.)
PMTs have been around since the 1930s, and remain the undisputed champs for the very lowest light levels. We love PMTs, but we have to admit that they're delicate and not that easy to use—they tend to be bulky, they need high voltage, and they need regular replacement. Most of all, PMTs are very expensive.
We've been working with several customers on developing products using Hamamatsu S13361 / S13362 series and On Semi (formerly SensL) MicroFC series SiPMs. They have different strengths, but both series are excellent devices that have far better linearity in analog mode than we initially expected. (There's a fair amount of doom-and-gloom about that in the specialized technical literature.)
Our first product design uses the Hamamatsu units, and can go from counting single photons to working in analog in dim room lights, with just the twist of a knob. Subsequently we've had the opportunity to do a couple of devices for time-of-flight lidar using the MicroFCs, which we developed from our existing IP. Recently we've been consulting on microplate and flow cytometry applications. All of these applications have in common that they're moving to the newer solid state option and away from PMT-based designs.
These applications are challenging enough without having to develop the photodetection hardware. With so much customer interest, we've been focusing on developing a series of SiPM modules that act as drop-in replacements for traditional PMT modules, including all their nice features such as wide-range voltage-controlled gain, ±5 V input, and selectable bandwidths from DC–200 kHz to DC–300 MHz. Our existing designs are available on a flexible licensing model that generates considerable savings compared with either purchased PMT modules or internally-funded development, and gives you complete control over your supply chain.
Because these technologies are new, we can provide customized proof-of-concept (POC) demos showing how they work in your exact application. We've delivered prototypes and POCs in as little as one week at low cost, so you can make a real-world engineering evaluation without sacrificing a lot of budget or schedule.
For more information on our SiPM/MPPC designs, or help with your low-light measurements, send us an email or give us a call at +1 914 236 3005—we're interested in solving your detection and system problems.