Testing Monazite using high resolution scintillators

This area is for discussions involving any fusion related radiation metrology issues. Neutrons are the key signature of fusion, but other radiations are of interest to the amateur fusioneer as well.
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Sean-Wiseman
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Real name: Sean Wiseman

Testing Monazite using high resolution scintillators

Post by Sean-Wiseman » Tue Dec 04, 2018 3:55 am

monazite-(Ce), (Ce, La, Nd, Th)PO4 (the most common member)
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独居石-解谱small.jpg
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who need LaBr?
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viewtopic.php?f=20&t=12537

John Futter
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Re: Testing Monazite using high resolution scintillators

Post by John Futter » Tue Dec 04, 2018 9:33 am

Sean
deadtime!!!!
or are you using "FAST" ADC's

Sean-Wiseman
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Re: Testing Monazite using high resolution scintillators

Post by Sean-Wiseman » Tue Dec 04, 2018 9:36 am

John Futter wrote:
Tue Dec 04, 2018 9:33 am
Sean
deadtime!!!!
or are you using "FAST" ADC's
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sorry
what is your means?
I do not understand ^_^

John Futter
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Re: Testing Monazite using high resolution scintillators

Post by John Futter » Thu Dec 06, 2018 6:04 am

Sean
The slewing of the spectra for the NaTl seem to be either too much dead time ie MCA not ready for next pulse or a damaged NaTl scintillator

I check sometime next week on the one i use (ortec 2"x2" Natl with a similar spectra

Sean-Wiseman
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Real name: Sean Wiseman

Re: Testing Monazite using high resolution scintillators

Post by Sean-Wiseman » Sat Dec 08, 2018 12:44 pm

John Futter wrote:
Thu Dec 06, 2018 6:04 am
Sean
The slewing of the spectra for the NaTl seem to be either too much dead time ie MCA not ready for next pulse or a damaged NaTl scintillator

I check sometime next week on the one i use (ortec 2"x2" Natl with a similar spectra
John
.
NaI's decay time ~250ns
presume dead time~250x5=1250ns
it can get 80,000 pulses every second.
80000cps is very big. so dead time is not a big problem if your MCA is fast enough.

My LaBr decay time about 20~25ns. ^_^
I also can sell it.

John Futter
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Re: Testing Monazite using high resolution scintillators

Post by John Futter » Wed Dec 12, 2018 6:46 am

80,000 pulaes per sec could incurr 10% deadtime or more with NaTl which will slew spectra and seriously widen FHHW response hiding the rest of the spectra
as for FAST ADC's this is what I use
https://www.fastcomtec.com/?id=409

Sean-Wiseman
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Re: Testing Monazite using high resolution scintillators

Post by Sean-Wiseman » Wed Dec 12, 2018 11:02 am

John Futter wrote:
Wed Dec 12, 2018 6:46 am
80,000 pulaes per sec could incurr 10% deadtime or more with NaTl which will slew spectra and seriously widen FHHW response hiding the rest of the spectra
as for FAST ADC's this is what I use
https://www.fastcomtec.com/?id=409
so you need LaBr.
LaBr decay time about 20~25ns.
NaI's decay time ~250ns
.
and 80000cps is very dangerous for man.
CZT will be better.

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