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TLV9061: Differentiator and Pulse Detection for Radiation Detector

Abdurrahman Zaim
Prodigy 60 points
Part Number: TLV9061


Tool/software:

I’m working on a radiation detector where the signal output consists of fast pulses, but I'm facing issues with pulse pile-up (overlapping signals) and varying signal amplitude. A fixed threshold comparator or Schmitt trigger doesn't reliably handle weak and strong pulses.

I’m considering using a differentiator circuit to extract pulse edges and feed them into a monostable multivibrator for a clean TTL output.

I need advice on:

  • Differentiator Design: Optimal RC time constant and low-power op-amps for high-speed signals.
  • Comparator: Should I use a high-speed comparator or a zero-crossing detector? Any recommendations with ultra-low propagation delay?
  • Monostable Pulse Generator: Suggestions for fast pulse processing circuits like 74HC123.
  • Noise Considerations: How to minimize false triggering due to noise in differentiator output?


the signal before the differentiator circuit that Ima planning to use looks like that :

my plan is to convert each peck to clear TTLPulse.

Any insights or reference circuits are greatly appreciated.

  • 0
    TI__Guru**** 167356 points

    Hello Abdurrahman,

    Are all three waveforms the same signal? What is the time and voltage scales for raw waveforms?

  • 0 in reply to Ron Michallick
    Prodigy 60 points

    Hello Ron,

    Yes, the waveforms represent the same signal from the detector output, but the amplitude varies—sometimes 3V, sometimes 2V, or more/less. The main issue is pulse pile-up, where multiple pulses arrive before the previous one has fully decayed.

    Regarding timing, these overlapping pulses typically occur within 30 to 100 microseconds of each other.

  • +1 in reply to Abdurrahman Zaim
    TI__Guru**** 167356 points

    Abdurrahman,

    Here is Differentiator Design, basically high pass filter with a high cutoff frequncy  https://www.ti.com/lit/sboa276 and https://www.ti.com/tool/CIRCUIT060028

    Consider adding diodes across the feedback resistors to compress larger signals.  After the Differentiator, a comparator can detect the input sudden rises. A slower version of the output (low pass filter) could be used to set a adaptive threshold. Is there meaning or data in the pulses? 

    I'm not sure why Monostable Pulse Generator would be helpful. 

  • 0 in reply to Ron Michallick
    Prodigy 60 points

    Hello Ron,

    Thanks for the references!

    Yes, the pulses contain meaningful data, as they represent detected radiation events. The challenge is ensuring that each pulse is accurately counted despite variations in amplitude and pile-up effects.

    The monostable pulse generator is intended to standardize the output into consistent TTL pulses, avoiding double counting or missing weak signals.

    Regarding the differentiator, I'll explore adding diodes across the feedback resistor for amplitude compression. The adaptive threshold approach using a low-pass filter sounds promising—I'll look into implementing that for better detection stability.

    Appreciate your insights!