10MHz synchronous photon counting

[Damian Gray]

Hi all,

In spite of my lack of experience with Labview, I have been asked to put together an application that could perform photon counting. I have seen a few related threads on this forum, but none of the examples I saw seemed to recquire the kind of time resolution I need. Let me explain:

I am trying to detect photons emitted during a "periodic" physical phenomenon occuring at 500kHz (worst scenario). So in order to characterize this phenomenon properly, I would need a time resolution of about 100ns (10MHz). Of course, the average number of photon during such a short amount of time is below 0, so I would need to accumulate the signal over a significant amount of periods to get a proper measurement. But is there a way to achieve such a time resolution by using Labview ? I currently use Labview 7.0 with DAQmx, a 6052E card and a BNC-2120 board. Feel free to suggest a hardware upgrade if you think it can solve my problem (I think a 6602 card would be more appropriate).

From what I have read, using continuous buffered event counting or buffered period measurement is the way to go. However, my first idea was to implement a simple counter whose value would be recorded each time a TTL pulse is detected (the counter would be reset at the end of the physical phenomenon) so that I could get time-resolved measurement after post-processing (even though the FIFO would be read in an asynchronous way). That way I was hoping to bypass the lack of "synchronous counting" feature of the E-series...

Ultimately my application would require additional features but if you could just point me the right direction that would be great ! Hopefully what I wrote makes sense... (sorry for the sloppy English by the way)

Thanks in advance,

Damian

[Mathieu_R.]

Hi Damian,

If you need to create counters with very specific behavior, you may be interested by our RIO devices. Thoses boards are based on FPGA (Xilinx) and doesn't require any VHDL knowledge, this, by using the LabVIEW FPGA module.

You simply create LabVIEW FPGA code, that will be compiled and run on the FPGA. Then, you can monitor your VI from the host PC (debug mode), or develop a little interface that will dialog with the FPGA personality, allowing you to read measured values and to write new consigns. Default clocking of the FPGA board is 40MHz, but it is possible to reach 80MHz, and more, if your code allow it (the content of the timed loop may be executable in 12,5ns at 80MHz).

We got two sort of FPGA PCI board, NI PCI-7811R and NI PCI-7813R, which provide only digital I/O (DIO); NI PCI-7830R, NI PCI-7831R and NI PCI-7833R wich provide multi-function I/O (MIO).

If you need advise about our products, contact us by phone (01 57 66 24 24 for our french office).

Cordially,