We are using DRS4 Rev.2.0 board.
We want to measure number of pulses generated by charge particle detector. These negative going analog pulses are very fast having rise time about 2nS.
We want keep threshold level to -20mV. We expected pulse rate to be about 100 to 200 Hz.
I need help to implement this in current DRS board with dead time free operation.
If you just want to count pulses, you do not need a DRS board. Just use a discriminator and a counter, that's much simpler. The DRS board is not dead time free.
Thanks for your prompt reply.
Along with pulse rate we also want see pulse shape as well as charge measurements. That is why we are exploring this option with our existing DRS Set-up.
I understand that. But still the board has some dead time which is dominated by the USB data transfer speed.
There is a way to perform the counting dead time free, but that requires the V4 board, which has a hardware comparator on all four channels (The V2 board has only one comparator and a multiplexer). The output of these comparators go directly to the FPGA, which can then trigger on these signals. In principle one could implement a hardware counter in the FPGA, which works practically dead time free. But this requires a new firmware which has to be written. Either you do it yourself using the Xilinx development tools, or you wait until I find some time to implement this, which could take a couple of weeks or even months.