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Testing Monazite using high resolution scintillators

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

Re: Testing Monazite using high resolution scintillators

Posted: Tue Dec 04, 2018 9:33 am
by John Futter
Sean
deadtime!!!!
or are you using "FAST" ADC's

Re: Testing Monazite using high resolution scintillators

Posted: Tue Dec 04, 2018 9:36 am
by Sean-Wiseman
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 ^_^

Re: Testing Monazite using high resolution scintillators

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

Re: Testing Monazite using high resolution scintillators

Posted: Sat Dec 08, 2018 12:44 pm
by Sean-Wiseman
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.

Re: Testing Monazite using high resolution scintillators

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

Re: Testing Monazite using high resolution scintillators

Posted: Wed Dec 12, 2018 11:02 am
by Sean-Wiseman
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
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and 80000cps is very dangerous for man.
CZT will be better.

Re: Testing Monazite using high resolution scintillators

Posted: Wed Jan 02, 2019 7:04 pm
by vince_Darmancier
I have used a 3" X 3" standart NaI scintillation probe for almost 10 years with decent resolution...I dont feel the need for a LaBr
calibration with Co60,
Image
Monazite
Image
Uranium ore
Image
Ba133
Image

Re: Testing Monazite using high resolution scintillators

Posted: Mon Jan 14, 2019 4:58 pm
by Sean-Wiseman
vince_Darmancier wrote:
Wed Jan 02, 2019 7:04 pm
I have used a 3" X 3" standart NaI scintillation probe for almost 10 years with decent resolution...I dont feel the need for a LaBr
calibration with Co60,
Image
Monazite
Image
Uranium ore
Image
Ba133
Image

Image

LaBr have Higher resolution and P/C than NEW Saint-Gobain NaI Crystals.
Whether this is needed is a comprehensive result. ^_^