one more spectrometer, homemade quadrupol

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Rapp Instruments
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one more spectrometer, homemade quadrupol

Post by Rapp Instruments » Sat Feb 13, 2016 12:37 am

Hello,
I justed finished my Quadrupol mass filter. It's a bit more difficult to construct and design the electronics than the sector spectrometer but it's worth to do because of the high sensibilty and the resolution.
I think most people here now the principles. Iones are deflected by high frequeny and static electric fields. If frequency, amplitude and the mass of the ion match the ion can pass the filter and can be detected.
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the quadropol is constructed on a NW40 feedthroug from aluminium parts, isolation is made by ceramic posts press fitted to the aluminium. The ion source is a electron beam source, the filament the usual small lamp.

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The electronic find place in a small box fitted to the feedthroug

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the quadropol can be used for analyzing the back ground gases in a vacuum plant.

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the differentation between the natural Neon isotopes is easy and interresting ist the spectra of a mixture of H2O and D2O

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This weekend I will try to see the small mass difference between D2 and He

More details and the circuit plan You will find on my home page http://www.rapp-instruments.de/Radioakt ... quadro.htm


Thomas

DanielSandner
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Re: one more spectrometer, homemade quadrupol

Post by DanielSandner » Sat Feb 13, 2016 11:49 am

This project is simply amazing.
I guess a Wien-filter would be much easier to build (especially the electronic), what is it's main disadvantage compared to this system?
Thank you also for your documentations on your website, this made me build my own nebular chamber and a small accelerator.
You could also use this spectrometer for high vacuum leak detecting.
Daniel Sandner

Rapp Instruments
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Re: one more spectrometer, homemade quadrupol

Post by Rapp Instruments » Sun Feb 14, 2016 11:11 am

Hi Daniel,

thanks for looking to my home page. If You have any questions about any project which don't fit to themes of this forum feel free to send a mail (info@rapp-instruments.de)

yes, a wien filter would be much easier to build, but it seperates ions by speed. If you want to seperate masses, all ions have to have the same speed. This is not easy done which normal ion sources.
If you look to the formula for a quadropol, the speed has no influence at all. Different speed of the ions only change the resolution but not the positions of the peaks.
Image

Just I made measurements with deuterium and helium. The small differences of the masses is visible.
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I think the small difference is the mass defect responsible for the energy you get in fusion reactions.

Thomas

I cannot proved the the difference between D2 and He anymore. Some more measurements showed that the peaks shift a little bit from run to run. Althoug the D2 peak was never lower than the He peak sometimes both are on the same position.

Thomas

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Werner Engel
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Re: one more spectrometer, homemade quadrupol

Post by Werner Engel » Fri Apr 08, 2016 12:34 pm

An really incredible solution! Congratulations!
I always thought about buying one from Pfeiffer - but 15.000€ for finding out you the quality of my vacuum?
How long did it take to machine the parts for you?

BR,
Werner

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Richard Hull
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Re: one more spectrometer, homemade quadrupol

Post by Richard Hull » Fri Apr 08, 2016 4:16 pm

Fabulous work!! Thanks for sharing this fascinating project with us. You are a fine instrument maker of the first rank.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
Retired now...Doing only what I want and not what I should...every day is a saturday.

Rapp Instruments
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Re: one more spectrometer, homemade quadrupol

Post by Rapp Instruments » Wed Apr 13, 2016 2:37 pm

Hi Richard,

thanks for the friendly words.

Hi Werner,

on my lathe it took less then one day to turn the parts, one day for assembling and round about two weeks to design and build the electronics.

Thomas

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Dennis P Brown
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Re: one more spectrometer, homemade quadrupol

Post by Dennis P Brown » Wed Apr 13, 2016 4:44 pm

Truly top notch work! Very impressive. Your handle name is well earned and appropriate!

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