Signal integration over ns time period

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Discussion Overview

The discussion revolves around the integration of a voltage signal over a nanosecond time period, specifically in the context of measuring time-of-flight spectra from photoelectrons. Participants explore various devices and methods for achieving this integration without gating the signal.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant inquires about the integration of a voltage signal over a nanosecond time interval and seeks recommendations for suitable devices.
  • Another participant suggests using a boxcar amplifier, but later clarifies that the original request is specifically for integration without gating.
  • A request for more details about the application is made, including questions about the periodicity of the signal and the intended use of the output.
  • The original poster describes the signal as coming from an MCP detector measuring time-of-flight of photoelectrons, with a focus on asymmetry between two detectors and measuring the carrier envelope phase of a laser pulse.
  • One participant recommends using a constant fraction discriminator (CFD) for measuring delays between pulses, citing their experience with specific devices like the Ortec 935.
  • Participants discuss the use of multi-channel scalers for producing time spectra from start and stop pulses.

Areas of Agreement / Disagreement

Participants express varying opinions on the best approach to integrate the signal, with some favoring the use of a constant fraction discriminator while others initially suggest a boxcar amplifier. The discussion remains open without a clear consensus on the optimal solution.

Contextual Notes

Participants have not fully resolved the specifics of the integration method or the implications of using different devices, leaving some assumptions and conditions unaddressed.

MAAB
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Hello,

I have voltage signal that is time gated up to ns. I want to integrate this signal over this time interval, how one can do this and which device can be used for that.

Regards
MAAP
 
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Boxcar amplifier is gating and integrating the signal, and I need only to integrate it!
 
Sorry for the short answer above - I was on the run.

Can you describe your application in a bit more detail? Is the signal periodic? Where does the gate or trigger come from? What do you want to do with the output signal? Do you want to integrate your voltage from a start to a stop trigger, and at the stop transfer the result to an ADC or similar?
 
sorry I was out of office
The signal is an output from MCP detector which measure the time of flight of the photoelectrons that are liberated from the atoms. So the gate is a short interval of the measured time of flight. actually I have two detector on the right and left and I want to get information about the asymmetry between the time of flight spectra. I don't want to transfer the result to ADC, but i will use it to measure the CEP (carrier envelope phase) of the laser pulse.
 
the signal has a frequency of 3.3kHz, I hope I answered your questions.
 
Thanks, that makes it pretty clear.

If the most important information is the delay between two pulses, then you probably want a constant fraction discriminator. We use Ortec 935 with avalanche photo diodes for timing experiments with single x-ray photons.

http://www.ortec-online.com/download/935.pdf

We used the output of the CFD as start pulse for a TDC and the periodic (352 MHz) "bunch clock" as stop, then fed the digitized time signal into a histogram memory to get a time spectrum of our photons.

These days you can get multi-channel scalers (MCS) e.g. from FAST, Ortec, and a few others that take the start and stop pulses and directly produce the histogram/time spectrum.
 
Thank you very much, It seems that it will work with your solution.
 
My pleasure. Let me know when you get results :-)
 
  • #10
for sure :-)
 

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