Analyzing signals from a radioactive source

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Discussion Overview

The discussion revolves around the feasibility of analyzing signals from a 57Co radioactive source using an ADC with a specific sampling rate. Participants explore the technical requirements for pulse height spectrum analysis and coincidence counting between different energy levels emitted by the source.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant inquires about the possibility of using a 5 GS/sec ADC to analyze signals from a 57Co source and mentions interest in pulse height spectrum and coincidence counting.
  • Another participant notes that the type of detector used is crucial, as the ADC cannot detect pulses directly and questions the meaning of "pulse duration" in this context.
  • A participant confirms the use of NaI(Tl) detectors and asks if they can be connected to the ADC, referencing a specific document for pulse shape information.
  • It is pointed out that a pulse width of 50 microseconds renders a 20 ns time resolution less beneficial.
  • One participant advises that amplifying the signal before connecting it to the ADC is standard practice and necessary for obtaining a clear signal.
  • A participant expresses the intention to set up a coincidence instrument using specific energy levels as start and stop signals, and seeks clarification on the use of various electronic components for this purpose.
  • There is mention of differing opinions on whether coincidence setups can be effectively achieved with flash ADCs or if conventional NIM modules are required.

Areas of Agreement / Disagreement

Participants express differing views on the suitability of using a flash ADC for coincidence counting and the necessity of conventional NIM modules. The discussion remains unresolved regarding the best approach for setting up the coincidence instrument.

Contextual Notes

Participants reference specific pulse durations and detector properties, indicating that assumptions about pulse shape and timing may vary based on the detector used. There are unresolved questions about the technical setup for coincidence counting.

Who May Find This Useful

Individuals interested in experimental physics, particularly those working with radioactive sources, signal analysis, and detector technology may find this discussion relevant.

Rajini
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Hello All,
Is it possible to analyze signals/photons/pulses from a 57Co source (strength 2 microCi) using a ADC (multihit readout) with 5 GS/sec? Just to look at pulse height spectrum..also I am interested to make a coincidence counting between 122 adn 14.4 keV levels! I heared that these ADCs are used to count pulse duration of less than 20 ns. But 57Co sources emits pulses in the order of microsec.
Thanks for your input.
Cheers.
 
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It will depend on what kind of detector you are using; the ADC itself can't detect pulses directly.
Also; what do you mean by "pulse duration" in this context? I assume you are interested in gamma radiation in which case there IS not pulse duration as such (only single photons which do not have a "shape"); the pulse shape will depend entirely on the properties of the detector.
 
Hello,
Yes I use NaI(Tl) detectors. Can I connect these detectors to ADC with 5 GS/sec? Will it work? When you view the signals from detector using a oscilloscope, the pulses look as in page 71 of this pdf document http://www.lanl.gov/orgs/n/n1/panda/00326399.pdf. The x-axis scale is what I meant as pulse duration..in that fig it is 50microsec.
Thanks
 
If your pulse width is 50 us, or 50,000 ns, having 20 ns time resolution will not help you much.
 
You're going to want to amplify your signal before putting it into an ADC, this is described in the document you provided and is a standard procedure and will give a nice signal as shown in fig 4.6. The pulse duration isn't to do with 57Co itself, it's the time response of the detector. A standard spectroscopy amplifier and ADC will have no issue with this.

If you wish to look at coincidences, you'll have to do some more complicated electronic setup than you are attempting at the moment, for a start, you'll need multiple channels in which to do a coincidence.
 
Hello, vanadium/e.bar.qoum:
Yes I want to set a coincidence instrument. 122 keV as start signal (it is the start of the emission of 14.4 kev) and 14.4 keV as stop signal. Although, I have CFDs, SCAs, TAs, etc, I prefer to use the flash ADC with 5 GS/sec. So thought of asking help! Some say it is only possible with conventional NIM modules..Is it true?
Regards,
Rajini
PS: How coincidence setup are done? How the signals are selected using TAs, CFDs, TACs,? Any info/materials/books for this works with pictures and exmaples..
 

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