Questions tagged [mass-spectrometry]
25 questions
13
votes
1 answer
Can a discrete dynode mass spec detector get "tired?"
In an electron multiplier (discrete dynode detector), one electron triggers the release of more electrons in a cascade.
Is it possible that a "large" number of electrons hitting the detector can temporarily (course of hours) reduce the number of…
ZachB
- 231
11
votes
2 answers
Is ultradense deuterium real?
I've found several articles discussing experimental evidence of a deuterium state of densities over $140 \textrm{ kg}/\textrm{cm}^3$:
F. Winterberg. Ultradense Deuterium. arXiv.
Shahriar Badiei, Patrik U. Andersson, Leif Holmlid. High-energy…
diffeomorphism
- 2,299
5
votes
1 answer
Velocity distribution in ion source (electron bombardment) for Bainbridge mass spectrometer
Consider the following schematics of a Bainbridge mass spectrometer
(Source: http://www.schoolphysics.co.uk/age16-19/Atomic%20physics/Atomic%20structure%20and%20ions/text/Mass_spectrometer/images/1.png)
Suppose the gas contains two sorts of atoms…
user47175
- 51
4
votes
1 answer
Experimental limits on anisotropies in the $e/m_{e}$ ratio
Currently the charge-to-mass ratio of the electron is known to 10 orders of magnitude.
However, i'm curious if:
Are there any experiments trying to bound the anisotropy of this ratio for different directions of space? Over what time does the data…
lurscher
- 14,933
3
votes
1 answer
How small of a depletion signal can the best modern mass spectrometers detect?
So I know the answer to this question varies widely across mass spec techniques, masses, and, of course, budgets, but my question is about the best case scenario for all of these variables (although I'm not really looking at proteins or anything of…
3
votes
2 answers
Why didn't accelerator mass spectrometry greatly improve the accuracy of carbon dating?
My understanding of the limitation of radiometric dating is that background radiation swamps the radiation from C14 once the remaining atoms get few enough in number. Accelerator mass spectrometry seems to actually count every atom in the sample,…
Noumenon
- 133
2
votes
2 answers
Is there a way to experimentally determine the true mass of C-12 isotope which is defined exactly as 12 amu?
As most you know the measurement of atomic masses has > 200 year old history and atomic masses were deduced on the basis of chemical reactions by meticulous chemists until the 1940s. Later, mass spectrometer became the tool for determining atomic…
ACR
- 312
1
vote
0 answers
Mass measurement in a Penning trap
My question is motivated by this paper. They are measuring the mass of a molecular ion in a Penning trap, and they are able to see a difference due to the fact that the molecule gets polarized (the motion is classical and non-relativistic). I was…
Alex Marshall
- 749
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1
vote
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Are ions in a flowing solution affected by magnetic fields
Are ions which has been dissolved in water affected by magnetic fields in any measurable way?
Basically, I want to measure different ions in a water solution. Would it be possible to build a mass spectrometer type sensor which subjects a stream of…
1
vote
0 answers
What is the physical meaning of a molecular fragment having two appearance energies?
Appearance energies are particularly import when it comes down to mass spectrometers that use electron impact bombardment. They typically denote the quantum energy value for fragmenting the molecule into two other molecules, for instance the…
Cavenfish
- 111
1
vote
1 answer
Atomic Structure History
I was reading a book about atomic structure history (Chemistry in Context by Graham Jill and John Holman), and got interested in few points which is not explained in the book.
"Calculations based on the results obtained by Geiger and Marsden…
Light
- 19
- 1
0
votes
0 answers
Looking for raw interferogram data / raw FID data from FT-IR / FT-NIR / FT-NMR
I'm trying to get my hands on some raw interferogram data / raw FID data from an FT-IR / FT-NIR / FT-NMR so I can run some tests using FFT with it (it needs to be real data). Here's a picture below of the data I'm looking for highlighted in yellow. …
Rick T
- 151
0
votes
0 answers
Uncertainties on negative mass spec intensities
I'm developing mass spectrometry (specifically, RGA-QMS or residual gas analysis mass spectrometry with a quadrupole) data reduction software and have encountered an issue with handling negative data.
My primary goal here is to calculate errors on…
0
votes
0 answers
Is mass spectrometry convenient to separate elements in a mixture?
Are particle accelerators coupled to spectrometers ever used to separate and extract different components of a mixture? If so, how much substance can be treated per day in this way? Would it be a viable way to treat tech waste?
0
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0 answers
What is the meaning of Scan Speed in case of a mass spectrometer?
For example if the scan speed is $15000 \frac{u}{s}$ then what does it mean? Since $u$ is a mass unit, then does $15000 \frac{u}{s}$ mean that the Mass Spec is able to scan mass of $15000$ per second?
