Liquid Scintillation Counting

Scintillation crystals, PMTs, voltage dividers etc...
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Steven Sesselmann
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Liquid Scintillation Counting

Post by Steven Sesselmann » 29 Nov 2018, 20:25

Hi All,

Does anyone here have experience with Liquid scintillation counting?

https://wiki.uio.no/mn/safe/nukwik/inde ... ntillation

Looks simple enough and should work with PRA, just not sure about how to rig up the PMT's. Would the scintillation liquid and sample be in direct contact with the PMT's or is it normally in a separate glass tube?

I have never seen one in the flesh.

Steven
Steven Sesselmann | Sydney | Australia | gammaspectacular.com | groundpotential.org | rephopper.com | beejewel.com.au |

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brehwens
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Re: Liquid Scintillation Counting

Post by brehwens » 26 Jan 2019, 04:31

A late reply...

The sample is mixed in with the scintillation fluid, in a "standard" scintillation vial that is opaque. The PMTs are not in contact with the sample.

I don't really know what kind of "resolution" one can get with these kinds of detectors. My experience is only of gross counting in the lab, when labelling cells with radionuclides, or to analyze swabs.
Karl Brehwens
Eskilstuna, Sweden.

Setup: 5 cm lead castle, 2mm copper lining. Gamma Spectacular Pro 2002, Sound Blaster Live! 5.1,
Primary detector: Scionix refurbished 2x2" NaI(Tl) well detector, 7.5% @ 662 keV

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Steven Sesselmann
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Re: Liquid Scintillation Counting

Post by Steven Sesselmann » 26 Jan 2019, 09:45

Thanks Karl,

Wouldn't it be better if one had some kind of coupling liquid between the PMT and the vial?

I'm thinking in terms of silicone oil or something like that, into which one could plunge the whole vial.

Steven
Steven Sesselmann | Sydney | Australia | gammaspectacular.com | groundpotential.org | rephopper.com | beejewel.com.au |

Vit Ladanyi
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Re: Liquid Scintillation Counting

Post by Vit Ladanyi » 28 Feb 2019, 23:52

Hello Steven,

We are using clear glass vials with low content of potassium to lower the background, and 2 inches PMT for liquid scintillation counting. The method is most effected for beta and alpha radiation. Spectrometry is possible for both aforementioned types of radiation. The glass vial should be as close to PMT photocathode as possible without special connection with the PMT screen.

Sincerely,

Vit
Brno, Czech Republic

Boris
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Re: Liquid Scintillation Counting

Post by Boris » 01 Mar 2019, 06:35

Hi Steven,

Long time no chat, I do have a crystal housing, with nothing inside (see att), the scintllator: BoDiPy in ethanol, no clue what it was used for.

Cheers, Boris.
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Steven Sesselmann
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Re: Liquid Scintillation Counting

Post by Steven Sesselmann » 02 Mar 2019, 18:03

Boris,

Thanks for posting, I have no clue what that is either...

Might be cool to make a container with a glass window that could be filled with various liquids and tested.

Tonic water, ink from fluorescent pens etc..

Steven
Steven Sesselmann | Sydney | Australia | gammaspectacular.com | groundpotential.org | rephopper.com | beejewel.com.au |

stamasd
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Re: Liquid Scintillation Counting

Post by stamasd » 15 Jun 2019, 22:23

I have used liquid scintillation in the past when I was a graduate student back in the 1990s. It was used for measuring beta activity in liquid samples. The sample would be intimately mixed with the scintillator then placed in a square-section glass vial (approximate dimensions 1cm x 1cm x 4cm). The vial was then inserted in a slot in the machine. The slot had a window behind which I assume the PMT was located. There was no use of a coupling compound between the glass vial and the window, just close mechanical proximity (close fit of the vial in the slot).
The isotope I used it most with was 32P.
I don't recall what the scintillator liquid was, but it had an eerie purplish fluorescence under fluorescent light; I assume it might have been a water-soluble anthracene derivative or similar.
Real name: Silviu Tamasdan

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