Analyzing signals from a radioactive source

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SUMMARY

Analyzing signals from a 57Co radioactive source with a strength of 2 microCi can be effectively achieved using a flash ADC with a sampling rate of 5 GS/sec. The NaI(Tl) detectors are suitable for this application, although the pulse duration of 50 microseconds necessitates signal amplification prior to ADC input. Coincidence counting between the 122 keV and 14.4 keV levels requires a more complex electronic setup, including multiple channels and possibly conventional NIM modules for optimal performance. Standard spectroscopy amplifiers can enhance signal quality, as detailed in the referenced document.

PREREQUISITES
  • Understanding of NaI(Tl) detector operation
  • Familiarity with flash ADC technology and specifications
  • Knowledge of signal amplification techniques
  • Basic principles of coincidence counting in radiation detection
NEXT STEPS
  • Research signal amplification methods for NaI(Tl) detectors
  • Learn about coincidence counting setups using TAs, CFDs, and TACs
  • Study the specifications and applications of flash ADCs in radiation detection
  • Explore conventional NIM modules and their role in coincidence counting
USEFUL FOR

Researchers, physicists, and engineers working with radiation detection systems, particularly those interested in analyzing gamma-ray signals and implementing coincidence counting techniques.

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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