“Our digital silicon photomultiplier technology is fully scalable and opens the door to new applications in areas such as medical imaging and nuclear physics,” says Rob Ballizany, vice president of Philips and general manager of Philips Digital Photon Counting. “With this new technology, we intend to bring the digital revolution to any application where ultra-low light levels need to be measured.”
Capable of counting single photons and detecting their arrival time with an accuracy of around 60 picoseconds, Philips’ digital silicon photomultiplier technology eliminates the power-consuming A/D circuitry associated with existing analog silicon photomultipliers.
Philips is looking for partners in selected applications to fully exploit the market potential of its new digital silicon photomultiplier technology.
but the pixel size is huge! How about the dark current induced false counts? It's necessary to cool it?
ReplyDeleteDear Anonymous,
ReplyDeleteIn silicon photomultiplier (SiPM) terminology, the word pixel describes an array of Geiger-mode photo diodes. So, on the array presented here, there are 8x8 pixels each containing 6400 Geiger-mode photodiodes. The dark count rate amounts to ~200kHz/mm^2, being the lowest compared to other SiPMs. One of the advantageous of the digital SiPM that is shown here is the possibility to switch off cells that generate a lot of dark counts.
Concerning the cooling questions: The digital SiPM can trigger on 1, 2, 3 or 4 photons. When triggering on more than 1 photon, dark counts are largely suppressed and cooling is not necessary. If you want to trigger on the first photon and achieve dead-times on the percent level, cooling to 0°C to 10°C is needed.
Best regards,
Carsten Degenhardt
Philips Digital Photon Counting
www.philips.com/digitalphotoncounting
Last year there was an interesting SPAD post here at the ISW blog of a presentation from the CNES CMOS Detector Workshop 2009 (link). The pdf file has a good overview of SPAD issues.
ReplyDeleteAlso, there was a precursor (?) annoucement last fall about a Philips chip with 8,188 SPAD devices on a single chip (link).
@ Carsten
You say that in one pixel of your chip there are 6400 SPADs. Are these basically acting as individual (or 2 or 3 or 4) photon detectors during a given exposure time, so that your digital output is a just a count of how many of the SPADs triggered? Or, are the SPADs continually triggering and getting quenched and reset, so that your output for a pixel is a set of 6400 values of how many times each of the SPADs in a pixel triggered?
Thanks for your clear answers!
ReplyDeleteOne more question, there are some dead zones on the detecting surface. Is this a problem compared to a PMD where the photocathode is uniform?
thanks in advance!
Dear CDM,
ReplyDeletethe SPADs are not continually triggering during the acquisition time. So you are right: The digital output is the count of how many SPADs triggered during the acquisition time.
@anonymous: the dead zones just lead to a loss of photons, i.e. a lower PDE. However, with 30-40% PDE (including this so-called fill-factor) SiPMs even today outperform many PMTs. BTW, the photocathode of PMTs is never uniform. Especially in multi-anode PMTs, gain variations of 1:4 are common.
Is this product available commercially. I have an acupuncture application in which I need to find acupuncture points in an automated way without the need of human intervention. I would like to evaluate SiPM especially the type phillips produces. How can I get to evaluate the prodict?
ReplyDeleteThanks
Shashank